The quality of a substance which resembles the diamond in luster.

A variety of quartz, agate is a translucent chalcedony that can be beige, brown or black in color. It takes its name from the Sicilian river which the Greeks knew as Achates (now the Drillo), that was rich in agate deposit. Truly beautiful with its multicolored motifs and patterned inclusions, agate has been used as ornamentation for some seven thousand years: beads of agate dating back to the Neolithic era were discovered in what is now Anatolia.
The patterns formed by its inclusions have inspired its different names: moss agate, cloud agate, landscape agate, tree agate, etc. Agate has long been reputed as a talisman and protector. Since the Greeks, it has been a favorite choice when carving intaglios or cameos. Jewelers, including Cartier, have also used agate to fashion dishes, bottles and other decorative objects. Hardness: 6.5 to 7.
Birthstone of Virgo. Brazil, Uruguay, United States, India, Madagascar, Mexico.
The color of this exceptionally rare stone (certain specimens of which can be more valuable than a diamond) changes with the light. Russian alexandrite is bottle green in daylight but a purple-red in artificial light. It was first discovered on the slopes of the Ural Mountains in 1831 on the birthday of Czar Alexander II, whose name it bears. Its colors, red and green, are that of Holy Russia, and it is the Russian national gem. Beryllium aluminate (chromiferous chrysoberyl). Hardness: 8.5. Brazil, Zimbabwe, Sri Lanka.
This stone is a deep red garnet with a violet hue. It owes its name to the city of Alabanda, near Ephesus in Asia Minor, which in ancient times was an important mining and cutting center for this variety of garnet. It was used in Persia from the Sassanid era (third century AD). Skillfully-cut almandine jewelry has also been found in the tombs of Frankish princes and kings, including that of Childeric I (fifth century). Almandine became extremely fashionable for its ornamental value in the seventeenth century (a number of “Louis XIV”'s almandine salt cellars can be admired in French museums), then under the Second Empire when its most popular form was faceted or polished into a cabochon. Iron aluminum silicate. Hardness: 7.5. Sri Lanka, India, Zambia,Vietnam, Brazil, Madagascar.
A variety of feldspar, its blue-green shade evokes that of turquoise or jade. It was traditionally given by the women of an Amazon tribe to the men, hence its name. It also exists in the Arabian desert, where Ancient Egyptians would come in the hope of finding a piece to carve into an amulet or beads. It was first adopted by Western jewelry during the Renaissance.Hardness: 6 to 6.5. Brazil, United States, India, Madagascar, Russia.

According to Greek legend, Helios, the god of the Sun, accepted that his son Phaethon should drive his chariot but Phaethon lacked the skill required to control the willful horses. Phaethon allowed the chariot to come too close to the Earth, causing a terrible drought. Zeus, anxious to avoid the worst, struck Phaethon with a thunderbolt that knocked him into the river Eridanus where he drowned.
Phaethon’s sisters, the Heliads, wept so bitterly that the gods transformed the siblings into poplar trees so that they could mourn their loss eternally.
Their tears were resin which turned into amber.
A golden-yellow, occasionally orange-tinted fossilized resin, amber has fascinated Man ever since the Neolithic age, when it was (and still is) gathered along the shores of the Baltic Sea.
Evidence that amber was used as a decorative object at such an early stage has been found.
But where exactly does amber come from? That it was found on shores suggests that it formed in the sea, yet specimens were discovered that imprisoned tiny insects.
It was not until 1811 with research by a Prussian scholar that amber revealed its origins: it is the fossilized resin of a variety of the pine tree (Pinus succinifer) that covered much of Northern Europe over thirty million years ago.
Amber has long been coveted for its beauty, but also for its mysterious “inhabitants”.
Indeed, these “insect inclusions” have always been a source of fascination.
Pope Urban VIII (1568-1644) owned a piece of amber containing three bees, while philosopher Emmanuel Kant always carried a piece of amber with an insect trapped inside.
Steven Spielberg enthralled movie-goers with a tiny mosquito inside a piece of amber in ‘Jurassic Park’.
The protector of plants and animals, amber was also known to protect and even cure humans, often ground into powder or burned for its fragrance. Amber has been used to make jewelry and rosaries.
The King of Prussia had a magnificent amber cabinet, entirely covered with an amber mosaic, which he gave to Peter the Great in 1716.
Stolen by the Germans from Tsarskoe Selo Palace during the war, it was never seen again.
Hardness: 2.5 to 3.
Baltic Sea, Santo Domingo.
This variety of quartz, the color of which varies varies from lilac to deep purple, has a legend. In it, the young nymph Amethyst (literally, “a remedy for drunkenness”) is transformed by Diana into a cold crystal to protect her against the unwanted advances of a drunken Bacchus. Once sober, and furious at Diana’s action, the god of wine emptied his cup over the crystal which turned violet in color.This legend has inspired amethyst’s reputation as a means of warding off drunkenness. It is traditionally chosen to adorn the bishop’s Episcopal ring.Amethyst was particularly fashionable during the reign of Queen Alexandra, wife of King Edward VII, who had a particular fondness for the color lilac. Silicon dioxide. Hardness: 7.5 to 8. Birthstone of Pisces. Its month is February and its planet is Jupiter. Symbol of happiness. Brazil, Madagascar, United States, Namibia.

The blue-green to pale blue color of this stone, which like emerald, is a silicate of aluminum and beryllium, inspired its name (“sea water”). The Indians and Ancient Egyptians sculpted it into amulets. Greek legend tells how seahorses stole these aquatic stones from the nymphs’ treasure and scattered them on shores where men would find them. Aquamarine has always been said to protect those at sea.
Cartier made this stone its own in the 1930s. One of the jeweler’s customers, Elsie de Wolfe, dyed her hair blue to match the diamond and aquamarine tiara which Cartier created for her in 1935.Hardness: 7.5.
Birthstone for the month of March.
Its planet is Saturn. Brazil, Madagascar,Afghanistan, Pakistan. Symbol of protection at sea and fidelity.
An optical phenomenon of a star-like figure caused by the reflection of light rays on inclusions.It can be seen in certain stones that have been cut as a cabochon.
The star ruby and star sapphire are two examples.

In the 1920s, Cartier created a series of miniature wristwatches, each less than a centimeter wide, decorated with precious stones.
Hugely successful, they were known as “baguette watches”.
They also evoked a type of cut, the “baguette cut” which Louis Cartier made popular as from the early years of the twentieth century.
Consisting of a narrow rectangle with a flat top, it is particularly admired for the skill it requires.
Beryls (from the Greek Berullos) are a family of stones that share the same crystalline and chemical properties.
Varieties include emerald and aquamarine.
Other beryls include pink beryls (known as morganites), golden-yellow beryls (known as heliodors), pale green beryls and (very rarely) red beryls.
Beryls were once used to make spectacle lenses.
Nero’s famous emerald loupe was probably a light green beryl.
The beryl’s optical properties inspired the French word bésicles and the German Brille, both meaning ‘spectacles’. Beryllium aluminosilicate. Hardness: 7.5. Brazil, Russia,Afghanistan, Pakistan, Zambia, Zimbabwe, Tanzania, Madagascar.
The name given to a round cut diamond with 58 facets: 32 facets above the girdle, 24 facets below the girdle, plus the table (the large uppermost facet) and the culet (the facet at the tip of the diamond).
The “brilliant cut” is the most frequent choice for diamonds as it brings out the full luster and brilliance of the stone.
It is the result of extensive research into physics and optical phenomena applied to the diamond, and was perfected around 1920.
A drop-shaped stone, the entire surface of which is cut in triangular facets.
This cut, invented in India, is still frequently used there for white diamonds, colored stones and fancy diamonds.
A type of cut that combines a cabochon cut on top and facets on the bottom.
It associates the softness of the cabochon with the sparkle of facetted stones.

A cabochon is a polished stone that has been given a rounded form.
Its name (from the Old French Caboche, itself from the Latin Caput, both meaning “head”) is inspired by its resemblance to the top of the skull.
Precious stones are always polished by hand and with a wheel.
The shape and polished finish of the cabochon produce fascinating shimmers of light and chatoyancy, in particular with deep-colored stones.
The cabochon has been one of the characteristic features of Cartier watches and writing instruments since the late nineteenth century: rounded polished stones decorate the winding crown of watches as well as the tip of fountain pens, propelling pencils and pens.
These cabochons can be fashioned from sapphires, rubies, emeralds or even coral and onyx. Cabochons can also be used in parures.

The expressions “calibrated rubies”, “calibrated diamonds”, etc. refer to a certain number of identical stones, having the same step cut and shape (usually square), which will be closely set in adjacent rows.

Cameo (from the Italian) is the low-relief sculpture of a colored stone, usually chalcedony, agate,amethyst or onyx.
The sculpting brings out theirdifferent colored layers.
The art of cameo was at its height during the Ancient Greek and Roman eras, and again during the Renaissance.
A very ancient unit of weight, standardized at the beginning of the twentieth century, the carat is used to measure the weight of precious stones to two decimals. One carat equals 200 milligrams.
The carat (ct or kt) is also a measure of the purity of gold. One carat represents 1/24 purity by mass. Precisely, the carat rating of the material corresponds to 1/24 of the mass of pure gold or platinum in the material divided by the total mass of the material. For example, 18-carat gold is 75% gold, 12-carat gold is 50% gold...

This translucent red-orange chalcedony has been used to make jewelry since the Neolithic era, when it was often fashioned into beads.
Its name is said to come from the cornel tree, a reference to the color of the flesh of its fruit.
A prized stone in Ancient Egypt, where its blood-red shade made it a symbol of life, carnelian was found on Tutankhamen’s breast plate.
The Persians believed it offered protection against the “evil eye” as well as protecting against venomous snakes and insect bites.
It has been carved into intaglios since Ancient Rome. Hardness: 6.5. Birthstone of Aries, Taurus and Scorpion. India, Yemen, Brazil, Uruguay.
This translucent yellow-green chrysoberyl owes its name to a beautiful optical phenomenon caused by the nature of its tubular inclusions which are revealed when the stone is cut as a cabochon: its blue-tinted opalescence is accompanied by moving streaks of light, similar to the pupil of a cat’s eye.
In ancient times it was known as cymophane meaning “wave-like”.
A similar effect can be produced by other stones when cut as cabochons.
However, in this case the term cat’s eye must be preceded by the name of the mineral, e.g. tourmaline cat’s eye, quartz cat’s eye, etc.
Beryllium and aluminium oxide. Hardness: 8.5. Birthstone of Capricorn. Brazil, Sri Lanka.
Chalcedony takes its name from Chalkedon, a former city in the ancient country of Bithynia.
An accumulation of microscopic quartz crystals, it is gray to blue to pale yellow in color in its purest form.
However, the presence of iron or nickel can alter its hue and its name: bright green chalcedony is called chrysoprase, red-orange chalcedony is known as cornelian, brown chalcedony is known as sard, agate is patterned chalcedony, onyx is black or black and white chalcedony, while jasper is chalcedony whose impurities give mixed shades, rendering it opaque.
Chalcedony is one of the largest families of the mineral realm.
Already popular in ancient times, its porosity means it readily absorbs stains.
Indeed, most chalcedonies on the market today are dyed, in which case they are known as blue agate, green agate, etc.
Natural or tinted, chalcedony has always been used for glyptics and is often chosen to sculpt cameos. Art Nouveau in particular brought this stone to the fore.Hardness: 6.5. Birthstone of Sagittarius. Uruguay, Brazil, India, Madagascar, United States, Czech Republic.
A gemmological term to describe a specific optical phenomenon:
whenever the fibers or inclusions in a cabochon-cut stone are arranged in parallel lines, they reflect an undulating band of light that resembles a cat’s eye.
This phenomenon has inspired the name of a variety of chrysoberyl known as cat’s eye. Other chatoyant gems include tourmaline, beryls and quartz.

From the Greek Khrysos meaning “gold” and beryllos meaning “bright stone”, chrysoberyl is a blue-tinted green-yellow to yellow-brown stone, which has been known since ancient times. Two very rare varieties of chrysoberyl are much sought-after today. These are alexandrite, which is green in daylight but red in artificial light, and cat’s eye whose specific structure creates an optical phenomenon known as chatoyancy. Certain exceptional chrysoberyls
can be seen in museums, such as the Hope (not to be confused with the diamond of the same name), a light green chrysoberyl weighing 45 carats that is part of the British Museum collections. Beryllium aluminium oxide. Hardness: 8.5. Sri Lanka, Brazil.

A crystalline quartz which, as its name suggests (from the Latin Citrus meaning lemon), is yellow in color, varying from pale to a deeper orange tint. Although occurring naturally, citrines are rare.
For this reason, an equivalent is often obtained by heating the citrine’s more common violet-tinted sister-stone, the amethyst.
Thanks to the possibility offered by such heat treatment to multiply the number of citrines available, jewelers can choose from among many large and flawless crystals. The citrine should not be confused with the topaz, an even rarer yellow stone, considered to be more refined because of its accentuated luster. Silicon dioxide. Hardness: 7. Birthstone of Gemini, Libra and Virgo. Symbol of sensuality. Madagascar, Brazil, Sri Lanka.
Measured by the visible presence of inclusions in a gem, clarity is one of the four “C”s used to appraise a diamond. International standards require that clarity be measured by a qualified professional using a loupe to enlarge the diamond ten times. The diamond is then graded according to a pre-determined scale based on the size, position and number of inclusions. Other precious stones are judged not by these criteria of clarity but rather by how “clean” they are. Indeed, a perfectly pure colored precious stone is a very rare thing. On the contrary, their inclusions diffuse the light and in certain cases give an attractive velvety aspect. As for the other colored stones, they are cut and sold only if they are totally or almost totally pure. There are a few rare exceptions to this rule, the work of contemporary jewelry designers who take advantage of the effects caused by the presence of multiple inclusions in gems that are habitually used only when pure (beryls, tourmalines, quartzes, etc.).
Diamond clarity grading scale: FL/IF Flawless or Internally Flawless. Loupe clean. VVS1 Very very small inclusion(s) VVS2 that is/are extremely difficult to see with a loupe. VS1 Very small inclusion(s) VS2 that is/are extremely difficult to see with a loupe. SI1 Small inclusion(s) SI2 that is/are clearly visible using a loupe but invisible to the naked eye when viewed via the crown. Alter the diamond’s brilliance. P1 Inclusion(s) that is/are clearly visible using a loupe but hard to see with the naked eye via the crown and which do not alter the diamond’s brilliance. P2 Large and/or multiple inclusion(s) that is/are clearly visible to the naked eye via the crown and which slightly alter the diamond’s brilliance. P3 Large and/or multiple inclusion(s) that is/are clearly visible to the naked eye via the crown and which significantly alter the diamond’s brilliance.
The quality whereby a mineral will split along the plane with the lowest atomic cohesion.
A gem is often chosen for its color, and yet the diamond is alone in having its own internationally recognized color scale, defined by professional bodies. This scale distinguishes white or colorless diamonds from fancy colored diamonds. Actually the white diamond offers a rich variety of nuances. Color is even one of the four qualities by which this precious stone is judged (one of the famous four “C”s, along with clarity, cut and carat). The diamond’s color is determined by comparing it with a master set of stones which have already been color-graded by experts. They are presented in a case. The stone to be color-graded is placed on a sheet of white bristol board next to one or more diamonds from the master set.

Because of its magnificent color, coral has been one of the most sought-after ornamental minerals since prehistoric times. In Switzerland, objects with coral decorations were found in Celtic graves dating back to the Iron Age. The Ancient Greeks believed it to be the petrified blood of Medusa.
Coral is a calcareous substance secreted by microscopic marine animals known as polyps to form a protective shell or external skeleton. These extend into branch-like forms, colored red by the presence of carotene. Coral can vary in intensity from blood red to pink, although a much-coveted white coral also exists, as does a keratinous black coral, now a protected species. Coral is harvested in warm waters, at depths of up to two hundred meters, after which it is sculpted and polished. Depending on its size it can be transformed into small sculptures, balls, brooches or delicate items of jewelry. Cartier has often used coral, preferably orange-tinted, to create elegant color combinations with emeralds or onyxes. Hardness: 3 to 4. Mediterranean (Italy, Algeria), Indian Ocean, Pacific Ocean (Australia).
Often used in jewelry today, cordierite varies in color from violet-blue to pale yellow depending on the angle from which it is observed. Named after French geologist Pierre-Louis Cordier (1777-1861), this mineral is more commonly known as iolite, from the Greek Ion meaning violet and Lithos meaning stone. The blue of a cut cordierite is similar to that of certain sapphires, hence its misnomer, “water sapphire”, although it is now illegal to use this name. Silicate of magnesium and aluminum. Hardness: 7 to 7.5. Symbol of trust and security. Sri Lanka, Brazil, Madagascar.

The generic term for a family of precious stones that consist of crystallized aluminum oxide: the ruby, the classic blue sapphire and sapphires of other colors, the rarest of which is a pink-orange Sri Lankan variety known as padparadscha (“lotus blossom”). Sapphires also occur in other shades, such as pink, mauve, yellow or green. Hardness: 9. Sri Lanka,Thailand, Cambodia,Australia, Madagascar.
The group of facets that forms the upper part of a cut stone (above the girdle).
In watchmaking terminology, the crown is part of the winding mechanism.
Lower part of the cut stones, below the round part (for diamond), or girdles (for the colorful stones).
The tip or point of the pavilion (lower part) of a cut diamond. The culet is the 58th facet of the brilliant.

A stone is cut so as to maximize its beauty, showing off its color, creating luster by the play of light on its facets and eliminating its defects. Diamonds are cut by the diamond-cutter and other stones by the lapidary, both highly qualified and experienced craftsmen.
First they cleave the stone with a hammer, then cut it with a saw and finally sculpt its facets using a wheel.
Diamonds can be worn rough or uncut in their natural octahedral or dodecahedral form. No one can say exactly when they were first cut.
Although confederations of lapidaries are known to have existed in twelfth-century France, diamond cutting only became commonplace in major European cities such as Antwerp, Bruges and Paris during the Renaissance. In the early seventeenth century Mazarin encouraged French diamond cutters to adopt the rose cut, a style developed in around 1520 in which the stone is cut into a dome shape with a flat base and a variable number of facets.
The Great Mogul and the Orlov are both famous rose-cut diamonds. This cut has however fallen almost completely out of favor because of its feeble luster. Early incarnations of the modern round cut appeared throughout the nineteenth century, such as the “double brilliant” with 34 facets, and the “jubilee” with its 88 facets. The brilliant cut as we know it today (the so-called “modern brilliant cut”) was perfected by an Antwerp diamond cutter by the name of Marcel Tolkowsky in 1919, after years of in-depth research into physics and optical phenomena. It reveals the full extent of the diamond’s luster, brilliance and fire. The brilliant has 58 perfectly regular facets: 32 for the upper section or crown, 24 for the lower section or pavilion, plus the table (the uppermost facet) and the culet (the tip of the pavilion).Diamond cutters have also perfected a number of fancy brilliant cuts, inspired by the classic round brilliant cut but with greater freedom in the number and shape of the bezel facets (the lozenge- shaped facets between the table and the girdle) or, more frequently, the number and shape of the lower girdle facets.
The resulting fancy brilliant cuts are generally named after their shape: oval, pear, cushion, navette and heart. Another variant is the mixed cut, when the facets of the crown and those of the pavilion are of a different style. The history of diamond cutting took a new turn in the late 1980s when Gaby Tolkowsky (Marcel’s great-nephew) created five “flower cuts” known as Marigold, Dahlia, Zinnia, Sunflower and Fire Rose.They are intended for rough stones that lend themselves with difficulty to other cuts, and for diamonds with a weak color. All these flower cuts have more facets, in particular around the culet, and are used for diamonds weighing more than 0.20 carats. The cuts used for colored stones are extremely varied. The final choice depends to a large extent on what the final color should be and, in particular when cutting transparent stones, what inclusions must be removed. Sometimes colored stones borrow diamond cuts, in particular the oval cut, cushion cut, pear cut, heart cut and briolette cut. Both diamonds and colored stones can also be given a step cut like an emerald cut (rectangular or square with sloping corners) or/and a baguette cut for small stones (a long, narrow rectangle with a flat top). Louis Cartier adopted the baguette cut in the early twentieth century, long before the Art Deco style made it fashionable.
Gems are cut in cities that have forged a reputation for their skill in this field. Traditionally, diamonds are cut in Antwerp and Tel-Aviv, to which can be added New York (specializing in large stones) and Bombay (for small stones).
For colored stones, all the producer-countries operate their own cutting workshops (Brazil, Madagascar, Vietnam).
Other centers enjoy an international reputation, however: Bogota (Colombia) and Jaipur (India) for emeralds, Bangkok (Thailand) and Sri Lanka for rubies and sapphires, and Idar-Oberstein (Germany) for other colored stones.
This extremely rare garnet, which occurs in every shade of green from dark to bright, owes its color to the presence of chromium and its nameto the Flemish Demant meaning “diamond”, because of this stone’s superb adamantine luster.
Indeed, its sparkling beauty would have made it a rival to the emerald, were it more resistant to scratching and above all larger in terms of carat weight.
Instead it was almost always used to surround other stones in rings and brooches.
Fabergé used it in Russia, and King Edward VII of Great Britain also appreciated its beauty.
The demantoid was very much in vogue in the late nineteenth and early twentieth centuries.
Silicate of calcium and iron. Hardness: 6.5. Russia, Africa, Korea.
This is the name given by Cartier to diamonds, whose structure contains nitrogen, causing their color to vary from champagne to golden orange, or from light to dark gray. “Diamants sauvages” is a registered trademark belonging to Cartier.
Extremely rare, unalterable, the hardest material known to man and brighter than a thousand stars, the diamond is the most prestigious of all precious stones, already worshiped by the Indians three thousand years ago.
Alexander the Great introduced it to Greece, where it became known as Adamas meaning “invincible”.
This in turn gave the word “diamond”.
This legendary name refers to a form of carbon which has crystallized in the upper layers of the Earth’s mantle, at a depth of one hundred and fifty to two hundred kilometers, in conditions of exceptionally high pressure and temperature. These crystals are then brought to the Earth’s surface by volcanic action, in the magma that surrounds them. India was the sole source of diamonds until the early eighteenth century, when deposits were discovered in Brazil then, in 1866, in South Africa. One of the diamond’s characteristics is its color, each nuance of which is officially graded.
There are several categories of “colorless” diamond (from “exceptional white” to yellow-tinted diamonds known as “cape”) and of fancy colors.
The diamond’s value is assessed in accordance with four factors, known as the four “C”s: cut, color, clarity and carat.
Fabulous stones, the symbol of eternal love, certain diamonds have left their mark on history.
The biggest cut diamond in the world is the Golden Jubilee (545.60 carats), a yellow-brown stone mined in 1986 in South Africa. Ten years later it was given to King Bhumibol of Thailand to celebrate his golden jubilee.
Through the creation of exceptional diadems and magnificent necklaces, transactions involving famous stones such as the blue Hope diamond (44.50 carats) and the pear-shaped diamond (69.42 carats) that Richard Burton gave to Elizabeth Taylor, and the use of platinum settings, Cartier’s name will forever be associated with this, the king of stones. Hardness: 10. Birthstone of the month of April. Its planet is the Sun. Symbol of love and fidelity.
South Africa, Angola, Australia, Brazil, Congo, Mali, Namibia, Russia, India, Venezuela, Zimbabwe.
A doublet is an assembly of two stones, by joining or fusion, intended to imitate a natural stone.
The assembled stones can be natural or synthetic stones, or even glass.
Garnet-glass doublets were very commonly used to imitate rubies and sapphires until the 1950s.
All kinds of doublets are still produced today, often joining together three or four elements.

A velvety, diaphanous green stone which belongs to the beryl family, the emerald has been worshiped for over three thousand years.
Emeralds were once mined in the Egyptian Arabian desert, between the Nile and the Red Sea.
However, the most beautiful specimens come from Colombia, whose mines have yielded such splendors as the emeralds of the Indian maharajahs, the Ottoman sultans, the shahs of Persia and those worn by Empress Eugénie.
In the 1920s and 1930s Cartier produced sumptuous emerald parures for maharajahs, the wife of banker J.P. Morgan, Princess Aga Khan and Barbara Hutton (using emeralds that had once belonged to Maria Pavlovna, wife of Grand Duke Vladimir).
Cartier commemorated its one hundred and fiftieth anniversary in 1997 with the creation of an exceptional necklace in the form of a snake, featuring two extraordinary pear-shaped emeralds weighing 205 and 206 carats.The emerald often features different kinds of inclusion. Often the emerald is clouded with inclusions. These are not classified as faults, but are evidence as to the genuineness of the stone.
They are termed as fluid inclusions, several of which form the jardin (or garden) of the emerald. A dark green emerald with inclusions is considered to be more valuable than a flawless pale green specimen. Silicate of aluminum and beryllium.Hardness: 7.5. Birthstone of the month of May.
Its planet is the Moon. Symbol of hope, appeasement, fertility. Colombia, Brazil, Russia, Pakistan, Afghanistan, Zambia, Zimbabwe,Tanzania, Madagascar. The most famous emerald mines are in Colombia (Muzo, Chivor, Pena Blanca, Coscuez) and Brazil (Itabira, Goias).
The name given to one of the surfaces of a cut stone.
Fancy color diamonds are recognized by the intensity of their color and their main (and in certain cases secondary) hue, all of which help determine their value.
Each color results from the stone’s specific chemical or structural properties. In certain diamonds, finely dispersed nitrogen atoms will produce different colors ranging from yellow to brown (daffodil, canary, cognac) depending on their quantity.
Traces of boron entrapped in the diamond’s structure give a blue color.
Green diamonds are believed to have been exposed to radioactive radiation while in the ground.
Pink diamonds are thought to result from a micro-dislocation in the lattice structure. The greater the dislocation, the redder the diamond.
A diamond with inclusions will vary from gray to black, depending on the extent of these inclusions, although black diamonds are rarely recorded as fancy colors.
The largest group of minerals in the Earth’s crust, their name is derived from the old German "Feld" meaning “field” and "Spath" meaning “mineral”.Feldspar occurs in many varieties, each with a specific chemical composition but sharing the same physical structure and characteristics. Different feldspar are used in jewelry for their colors and iridescent quality. The most precious varieties are labradorite, moonstone, sunstone and amazonite.
The term used to describe a fissure in a crystalline stone. If the stone is in its growth stage it will close around the inclusion and trap any substances there.
Because these substances are often liquid, bubbles form in the stone hence this term. Ceylon sapphires feature a characteristic type of delicate fluid inclusion known as “fingerprint inclusions”.

Garnets are one of the biggest families of the mineral realm. Contrary to popular belief, not all garnets are red.
A garnet can in fact be any color except blue. This is because while they all share the same cubic crystalline structure their chemical properties, although similar, can vary and this modifies their color.
Whenever a jeweler refers to a garnet without further qualification he is referring to a pyrope, a dark red stone whose shade is that of the color garnet. The other stones in this group are known either by their specific name, or as a garnet, but modified by an indication of their color.
Although garnets are often a shade of red, such as almandine which is a deep red with tinges of purple, rhodolite is pink and the very precious demantoid is emerald-green. Hessonite or cinnamon stone is dark orange, spessartite is yellow-orange and tsavorite, a recently discovered variety, is a strong green. Silicates of aluminum, magnesium, iron, manganese or calcium. Hardness: 6.5 to 7.5. Birthstones of the month of January.
Their planet is Mars. Symbols of fidelity, courage, energy. India, Vietnam, Afghanistan, Russia, Zambia, Madagascar, Australia, Brazil, China,Tanzania.
A mineral or organic substance used in jewelry.
The only factors that distinguish gemstones from other minerals are their beauty and rarity.
Such rarity is to a large extent what determines their monetary value, diamonds, rubies, sapphires and emeralds being the rarest and therefore most valuable of all.
Gems are not always minerals: organic substances such as pearls, amber and coral are also classified as gems.
Certain gems such as apatite, diopside, hematite, pyrite and tourmaline are also used in homeopathic medicines.
This word can have different meanings in jewelry terminology.
It refers to a unit of weight for fine pearls, one grain being equivalent to a quarter of a carat or 0.05 grams.
The grain is also a shaving of metal lifted from the mount then bent around a stone to secure it in place, a technique known as a “grain setting” or “millegrain setting”. Cartier used this setting in the early twentieth century to set diamonds in platinum.
In 1822 German mineralogist Friedrich Mohs (1773-1839) established a scale for measuring the relative hardness of stones that is still in use today (note that hardness has nothing to do with the fragility of a stone, i.e. its resistance to knocks.) Lapidaries must pay attention to a specific characteristic of hardness, resistance to abrasion, as this determines how they adjust their wheels. Friedrich Mohs’s scale, which bears his name, is based on the relative hardness of minerals which he measured in terms of their resistance to scratching with a pointed object. The Mohs scale is divided into ten grades, with no specific ratio between each one, as follows: (1) talc (2) gypsum (3) calcite (4) fluorspar (5) apatite (6) orthoclase (7) quartz (8) topaz (9) corundum (10) diamond.
This variety of beryl takes its name from the Greek "hêlios" (sun) and means “gift from the sun”. The color of this limpid stone varies from bright yellow to a green-yellow, and is due to the presence of uranium oxide, which makes it slightly radioactive. Given their often large size, heliodors are an ideal stone for solitaires. Silicate of aluminum and beryllium. Hardness: 7.5. Symbol of wisdom, power. Madagascar, Afghanistan, Brazil, Ukraine.
This term describes either a foreign body, be it liquid, solid or gaseous, that was trapped inside a gem during the course of its formation, or lacunas, i.e. cavities within the stone’s structure. Solid inclusions can be polyhedral crystals, crystalline needles (often found in garnets and quartzes) and bunches of crystalline fibers (such as amphiboles in emeralds).
Inclusions can reduce the value of a gem if they diminish its luster or make it more fragile. They can however give the stone a special attractiveness when they cause asterism or chatoyancy, when they form delicate patterns in agates, or when they combine to form an emerald’s beautiful jardin.
A precious indication of a stone’s past, inclusions are also a means of distinguishing natural gemstones from synthetic imitations.
A decoration created by incising the surface of a colored or precious stone. Intaglio has been used to make seals since ancient times.
Play of color of some gems caused by dispersion of light in cracks and flaws, resulting in the color of the rainbow (Latin iris = rainbow).

From the Latin eboreus, ivory is a phosphatic secretion that forms the tusks of elephants and certain other animals, and which has been sculpted into decorative objects since the Paleolithic era. The Ancient Egyptians, Greeks, Etruscans and Romans were all skilled ivory carvers, as were the Japanese, Chinese and Indians. The town of Dieppe was for many years France’s most important ivory-carving center. Today elephants are a protected species and consequently all ivory on the market should come from existing stocks. It is fashioned mainly into ornamental objects, necklaces and bracelets. Ivory has only rarely been used by Cartier as the main inspiration for an object, with remarkable results: in 1919 the jeweler created its so-called “Sudanese bracelets”, a series of astonishing African-inspired bracelets in ivory, decorated with enameled gold, coral or onyx and diamonds. Examples of more classic creations are the precious shafts of pen-holders and the handles of paper-knives, sometimes enhanced with enamel, which the jeweler made in the early years of the century. Hardness: 2 to 3. Africa.
Jade in fact describes two minerals, jadeite and nephrite, with a very similar appearance. Both are very hard, varying in color from milky white to dark green. Their shared name comes from the Spanish piedra de la ijada (literally “stone of the flank”), as the conquistadors who discovered it in America believed it could cure diseases of the kidney (“kidney” is also the origin of the word nephrite).
The Chinese adopted jade over four thousand years ago to sculpt jewelry and precious accessories, as did pre-Colombian American civilizations shortly after. Since then sculptors and jewelers have continued to carve and polish jade.
Both the Mongol emperors and the Indian maharajahs were passionate about jade. It was also very much in vogue in the twentieth century, promoted by the Art Deco style.
Cartier transformed jade into some truly marvelous creations, matching it with other precious materials to form bold color combinations. In 1928 an American magazine article remarked on this: “Parisian women look longingly in Cartier’s window, where the new bracelet collections are displayed, blending jade with lapis, jade with sapphire or jade with topaz.”
However, jade goes back much further in Cartier’s history, with the first jade jewelery dating back to 1913. Jadeite: double silicate of aluminum and sodium. Nephrite: basic silicate of magnesium and calcium with ferric iron. Hardness: 6 to 6.5 (nephrite) and 7 (jadeite). Mexico, New Zealand, China.
The collective noun for the fluid inclusions of an emerald.

A microcrystallized quartz rendered opaque and colored by the presence of clay or iron oxides.
Jasper occurs in many different shades, including multi-colored and patterned specimens.
For this reason it is usually known under a variety of names that evoke its origin or appearance: riband, jasp-agate, Egyptian, leopard, etc.
One of the most coveted forms of jasper is the heliotrope, which has a uniform green shade, speckled with red spots of iron oxide which resemble drops of blood, hence its other name of bloodjasper. It has often been used for glyptics in Christian art. Readily available, jasper has been used for ornamental purposes (jewelry, amulets, decorative objects) by civilizations everywhere since prehistoric times. Hardness: 6.5 to 7. Birthstone of natives to Aries. Russia, India, Sicily, United States, Africa.
In order to avoid confusion with “carat”, the unit of weight for precious stones, the German word karat, usually abbreviated to the letter “k”, has been adopted as a measurement of the fineness of gold. One karat equals 1/24th part of pure gold in an alloy: 24k gold is therefore pure gold.The word itself derives from the Greek keration, an ancient unit of currency that was worth one third of an obol (one eighteenth of a drachma). 18k gold comes in several colors, which can be the result of different alloys: • Yellow gold: 75% gold, 12.5% silver, 12.5% copper • Red gold: 75% gold, 25% copper • Pink gold: 75% gold, 21% copper, 4% silver • Green gold: 75% gold, 25% silver • Grey-blue gold and blue gold: contains an iron alloy • Purple gold: contains the same iron alloy plus silver, copper and aluminum • White gold: in jewelry, 75% gold and an alloy of palladium, copper, silver and iridium; in watchmaking, 75% gold and an alloy of palladium, copper and zinc. (The exact proportions of metals used to create the white gold alloy used by Cartier remain strictly confidential). Legal standards of fineness for gold in France were set on the nineteenth day of the second month of the Republican calendar in the year VI (November 9th, 1797) at 920/1000th (22k), 840/1000th (20k) and 750/1000th (18k).Adding 2/24th of another metal to 24k pure gold produces 22k gold, and so on. Note that adding another metal, usually silver and/or copper, will harden gold which, when pure, is too malleable.
This attractive lilac-pink to mauve stone was identified and made popular among jewelers by American mineralogist George E. Kunz, after whom it is named.
Unfortunately, kunzite splits easily when being cut. Cartier used it in 1991 for the brooches in the Route des Indes collection. Spodumene (silicate of aluminium and lithium). Hardness: 7. Madagascar, Brazil.
The structure of this generally blue-gray stone in minute parallel slivers creates bright flashes of color that resemble the wings of certain butterflies. These colors differ depending on the stone’s origin and reveal their full beauty when it is cut as a cabochon.
Cartier has used a gray-blue variety for its mystery clocks.Silicate of calcium and sodium. Member of the feldspar group. Hardness: 6 to 6.5. Canada, Finland, Norway.

This opaque stone, the Latin-Persian etymology of which (“azure stone”) describes its color, was one of the first to be used for its decorative qualities: lapis-lazuli beads dating back to seven thousand BC have been found in Mehrgarh at the foot of the Baluchistan mountains in Pakistan. Its azure-blue shade, which varies in intensity depending on how much of its principal mineral, lazurite, it contains and which is often spangled with tiny dots of pyrite, has made this a much sought-after stone ever since. For thousands of years the stone that Marco Polo described as “the most beautiful azure in the world” was transported from its principal deposits in Afghanistan and Iran as far as China, Egypt and Europe where it was transformed into precious objects, jewelry but also a pigment, known as ultramarine blue in Europe.
Cartier has made extensive use of lapis-lazuli as one half of one of the jeweler’s favorite color combinations, blue and green.
Louis Cartier frequently matched lapis-lazuli with turquoise for his Egyptian-inspired creations, and with coral for his so-called “Chinese” creations.Stone whose principal component is lazurite (sulfur-rich aluminosilicate of sodium and calcium).
Hardness: 5.5 to 6. Its planet is Jupiter. Afghanistan, Chile, Iran.
This is the sparkling effect produced by the reflection of light as it strikes the surface of a stone. Its intensity is determined by the refractive index of the stone and how skillfully it has been polished, and can be altered if the stone contains too many inclusions.
The characteristic luster of the diamond, the brightest of all, is almost equaled by other gems with a high refractive index, such as zircon and demantoid.
Depending on its nature, luster can be vitreous, resinous, waxy, pearly or silky.
An assortment of different-sized but small cut diamonds.
This spotted green, malleable stone is believed to take its name either from the Greek malakhê (the mallow plant) or from the Greek malachos meaning “soft”. Once cut, it reveals a concentric pattern of light and dark layers. First used by ancient populations in Asia Minor and the Egyptian deserts, jewelers particularly appreciate its beauty. Malachite has been worn as a talisman or used in powdered form as eye make up, to cure nausea, and as a green pigment for artists. Basic carbonate of copper hydrate. Hardness: 3.5 to 4. Cyprus, Russia, Congo.

An oval cut stone that is tapered to a point at each end, also known as a navette cut, from the French word for a weaver’s spindle, when applied to colored stones. It is most often used with diamonds.

The most precious member of the feldspar group. A translucent milky white, its shimmering silvery or pearly aspect is known as adularescence (after the Adula mountain group in the Swiss Alps where this gem was first found.). Best served by a cabochon cut, its pale blue tint and sheen, reminiscent of moonlight, were particularly appreciated by the Art Nouveau style. According to legend, the steps leading up to the Moon temple of Anuradhapura (Ceylon, twelfth century) were adorned with moonstone mosaics. It is still possible to visit the ruins of this temple.Double silicate of aluminium and potassium. Hardness: 6. Birthstone of the month of June. Symbol of love. Sri Lanka, Myanmar (formerly Burma), Madagascar, United States (including Hawaii).
This peach-blossom pink beryl with hints of carmine was the favorite stone of John Pierpont Morgan, a famous American banker, gem enthusiast and an important customer and personal friend of Louis and Pierre Cartier. It was named in his honor by mineralogist G. F. Kunz. Its color is due to the presence of lithium oxide and traces of cesium, a rare alkali metal. Hardness: 7.5. Madagascar, Brazil, United States, Mozambique, Afghanistan.
Cf. Marquise.

One of the stones, along with jadeite, known as jade. Originally from China, it is more common and less hard than jade. Basic silicate of calcium and magnesium. Hardness: 6 to 6.5.
A knock to the surface of a cut stone, in particular around the edges.

A slightly translucent chalcedony that is either black or with alternating black and white layers.
Its translucency inspired its name, from the Greek onyx meaning “nail”. However, the majority of onyxes on the market today no longer present this translucent quality as they have been dyed black, a technique that goes back to ancient times.
Onyx has always ranked among Cartier’s favorite stones. In the 1910s the jeweler chose it for its contrast, either to highlight the purity of rock crystal or the sparkle of diamonds, or to set off the bright colors of coral, emerald or turquoise.
Indeed, many of Cartier’s jewelry creations used all three elements in superbly elegant marriages of black, brightness and color.
The onyx-diamond couple was perfect for sophisticated evening jewelry, but also for mourning jewelry which women wore at the turn of the century. Cartier’s famous panther pavé, created in 1914, uses diamonds interspersed with spots of onyx.
Since then it has lent itself to watches, jewelry and vanity cases, or as a decoration for evening bags.Hardness: 6.5. Brazil, Argentina, Uruguay, Madagascar, Mexico, United States.

This stone, whose magnificent shimmering highlights (or “play of color”) are caused by the diffraction of light by an orderly arrangement of minute spheres of silica, offers many varieties. Those used in jewelry are “precious”, as opposed to “common”. Harlequin opals are a milky white color and reflect bright flashes of light in every conceivable color. Fire opals, as their name suggests, are red with red-orange highlights. The rarest variety, the black opal, is very dark with multi-colored highlights. Opal has been known to Man since the dawn of history, if the etymology of its name (the Sanskrit word upala meaning “precious stone”) is any indication. Ancient and Arabic civilizations believed it had protective virtues, and thus used it to create endless amulets, talismans and jewelry. In contrast, nineteenth century France accused the opal of bringing bad luck. Opal was brought back into favor by jewelers in the Art Nouveau period. In 1903 Louis Cartier created a magnificent heart-shaped opal pendant for the celebrated Australian soprano Nellie Melba.Hydrous silicon dioxide. Hardness: 5.5 to 6.5. Birthstone of October. Australia, Mexico, Brazil, United States.
A milky iridescence caused by the multi-directional diffusion of light that is characteristic of the common opal (hence its name). Certain quartzes and sapphires can also be opalescent.
A mineral which, pure or as a compound, contains one or more specific chemical substances in proportions which may be industrially isolated.
Adjective describing a substance produced by a living organism. Organic gems used in jewelry are pearl, coral and shell.
The name given to the iridescent luster of pearls, so-called because it resembles the glow of the rising sun. The intensity of a pearl’s orient is one of the criteria by which it can be judged.
Opaque stones such as malachite and lapis-lazuli.
This yellow-green stone, also called olivine when it is an olive-green shade, was introduced to Europe by knights returning from the crusades. Extracted from mines on Zabarjad, a small island in the Red Sea also known as Saint John's Island, it captured the imagination of Eastern civilizations almost three thousand years ago. Reaching this island was so difficult that sailors named the peridot topazion from the Greek word meaning “to seek”, a name it kept for many centuries before being supplanted by the French term. The peridot is associated with diamonds, as it is one of the components of the diamond’s matrix rock, kimberlite, to which it gives its distinctive blue-green color. Peridot was the favorite stone of King Edward VII. Its popularity surged in the early twentieth century and has never diminished. Silicate of ferrous magnesium. Hardness: 6.5 to 7. Birthstone of the month of August. Its planet is Saturn. Symbol of health and protection. United States, Australia.
This Singhalese word (literally, “color of the lotus blossom at sunset”) is the name of the rarest of non-blue sapphires. Indeed, the padparadschais a beautiful pink-orange shade. Hardness: 9. Its planet is Venus. Sri Lanka.
From the Greek para meaning “akin” and genesis meaning “birth”, this term refers to a group of minerals that form in contact in the same environment. The paragenesis of a gem, i.e. the minerals with which it forms, can influence its growth. During its formation a mineral can also “trap” elements from its paragenesis within its structure. These will become inclusions.
A group of gems set very closely together so as to cover an entire surface.
The lower part of a cut stone, underneath the girdle (for diamonds) or the rondiste (for colored stones).

Pearls were known to the most ancient civilizations in China, Egypt, Greece, Persia and Rome. They have been worn as ornamentation for at least two and a half thousand years: the oldest known pearl necklace (three stands of seventy-two pearls) dating back to the sixth century BC was discovered in the burial chamber of an Achaemenian prince. In myths and legends pearls are often associated with tears: in Japan they are the tears that a heartbroken princess shed into the sea; for the Greeks they are the tears of Venus; for the Romans they are the solidified tears of angels; in the Muslim religion they are the tears that Adam and Eve cried for their sins. This doubtless explains why pearls have always symbolized love and purity.Today one should always differentiate between fine pearls and cultured pearls. All pearls are a more or less spherical concretion formed by layers of mother-of-pearl (or nacre), secreted by the mantle of sea pearl oysters or fresh water mussels. Fine pearls are formed when this secretion is a natural reaction to the intrusion of a small parasitic worm into the mantle.
As fine pearls grew increasingly rare, nineteenth-century producers decided to adapt a time-honored technique to artificially incite mollusks to secrete mother-of-pearl. This process consists of inserting a foreign body (in this case a fragment of nacre) under the mantle to trigger a reaction. The first attempts at producing cultured pearls took place in China and Japan, although the first real successes were achieved in Australia in 1900. Japanese cultured pearls were launched on the market in 1920. This was perfect timing as by then fine pearls were commanding astronomical prices.
Three years earlier Cartier had purchased premises on New York’s 5th Avenue in exchange for a double strand of pearls! Since 1950, whether from Japan or elsewhere (in particular Tahiti and its famous black pearls) cultured pearls have almost completely superseded fine pearls.The quality – and therefore the value – of a pearl is judged in accordance with the following criteria: the intensity of its orient (the iridescent luster produced when light hits the layers of nacre); the beauty of its color; the symmetry of its shape, be this spherical, pear or button; the evenness of its “skin” and of course its size and weight, measured in grains for fine pearls (one grain equals 0.05 grams) and in carats for cultured pearls. Hardness: 3.
Literally,‘fine stone’.
In France, this is the name given to transparent or opaque natural stones (which can also be called ‘ornamental stones’ when they are used to make decorative objects), as opposed to ‘precious stones’. In France, this term has replaced that of ‘semi-precious stones’.
Other French-speaking countries use the term ‘precious stones’ to describe all types of stone.

A selected specimen of any valuable gemstone that is sufficiently rare, beautiful and lasting to be used in jewelry. Generally speaking, precious stones are transparent or translucent.
In France, a decree issued on November 29, 1968 restricts the use of the term “precious” to just four stones: the diamond, the ruby, the sapphire and the emerald. Other gems are called fine stones.
The most well-known variety of garnet, the pyrope is a fiery-red stone that takes its name from the Greek pyropos meaning “fiery-eyed”.In ancient times the pyrope was classed in an indistinct group of red stones known as carbunculus meaning “red-hot coal”.
It is, along with the peridot, a characteristic mineral of kimberlite and can guide diamond-hunters in their search. Silicate of aluminium and magnesium.Hardness: 7 to 7.5. Russia, United States, Australia, Brazil,Tanzania.

Quartz (from the German quarz) is a large mineral group whose crystals are composed entirely of silica, found in abundance in the Earth’s crust. Totally colorless quartz is known as rock crystal, although most quartz occurs in different shades to which it owes its different names: citrine is yellow, amethyst is purple, and prasiolite is green. Others have simpler names, such as pink quartz or smoke quartz. All varieties of quartz can contain inclusions which alter their appearance and give them their special charm.
Examples include Venus-hair quartz, which contains golden-yellow needlelike rutile inclusions that resemble hair and flèches d’amour quartz (literally “love arrows”) with its needles of black tourmaline and iris quartz whose small internal flaws or fissures cause an iridescent effect. Sometimes inclusions can be present in such quantities as to render the quartz almost opaque.
This is the case with both jasper and pink quartz. Cartier often used the latter to make bases for decorative objects or sculpt small animal statues. Inclusions can also cause specific optical phenomena, such as spangled aventurine quartz or tiger’s eye quartz, so-called because of the slender, yellow crystalline needles it contains.
Translucent varieties of quartz include chalcedonies, the most precious of which is the chrysoprase whose bright green color is due to the presence of nickel. Silicon dioxide. Hardness: 7. Birthstone of natives to Taurus, Leo, Libra and Sagittarius. Pink quartz symbolizes tenderness while rutilated quartz symbolizes passion. Rare varieties of quartz are chrysoprase (Australia, Brazil, United States),“flèches d’amour” quartz (Brazil) and pink quartz (Brazil).
Deflection from a straight path of a ray of light when passing from one medium, such as air, into another, such as a precious stone.Certain substances, known as birefringent or anisotropic, can split the ray of light in two.

The capacity to refract - i.e. to cause to deviate - light. Of all precious stones, the diamond is the most refractive (in other words it has the highest refractive index). The higher the refractive index, the longer the ray of light will take to travel through the stone, and the greater the luster.
A variety of garnet that owes its name (from the Greek rhodon meaning “pink” and lithos meaning“stone”) to its pink shade. Its color can darken to become almost purple, depending on the proportions of iron and magnesium it contains. Silicate of aluminum, magnesium and iron. Hardness: 7.5. Zimbabwe,Tanzania, Sri Lanka.

This transparent quartz was appreciated by all the ancient civilizations and has never ceased to inspire jewelry creations.
Its name comes from the Greek krystallos meaning “ice”, because of its resemblance to frozen water. In the Western world, rock crystal was particularly prized in the sixteenth and seventeenth centuries, as shown by the abundance of rock crystal objects including bowls, ewers, boats and caskets that can now be admired in museums throughout Europe.
The purity of rock crystal matched the spirit of the Art Deco style, and thus came back into fashion.
Cartier made poetry of this mineral, with round or rectangular brooches and bracelets, often combining it with onyx to create an elegant contrast, or using it to further emphasize the beauty and sparkle of diamonds.
In 1932 Gloria Swanson purchased two extraordinary bracelets from Cartier. They were fashioned from several dozen semi-circles of rock crystal enhanced with diamonds on a supple and elastic platinum mount.
Most of Cartier’s legendary mysterious clocks feature a rock crystal dial. Silicon dioxide. Hardness: 7.
Birthstone of Leo. Symbol of eternity. United States, Brazil, France.
The term used to describe a rock or a crystal in its natural state (before cutting or polishing).
A diamond that has not yet been cut. Although the diamond’s atoms crystallize in the cubic (isometric) system, it is very rarely found in cubic form.

This exceptional precious stone is a variety of corundum that owes its red color (hence its name, from the Latin rubeus meaning “red”) to the presence of chromium. Its hardness and rarity rank it just behind the diamond.
The ruby has always been held in the highest possible esteem. Indeed, the Indians called it ratnaraj, Sanskrit for “queen of precious stones”, or ratnayaka, “the first of all precious stones”.
The Indian princes were collectors of the most precious specimens, among them Nizam al-Mulk, Maharajah of Hyderabad, whose solid gold throne was decorated with a hundred or more rubies weighing 100 to 200 carats each.
For fifteen centuries the most exceptional rubies were mined in the Mogok valley in Myanmar (formerly Burma), immortalized by Joseph Kessel in “The Valley of Rubies”.
Some of these rubies possess the most coveted shade, a deep red tinged with purple known as “pigeon blood”. However, a complete lack of control over how these rubies were mined means they are now exceptionally rare.
The biggest gem-quality ruby in the world, weighing almost 250 carats, is set in the crown of Saint Wenceslas which is conserved in Saint Guy’s cathedral in Prague.
The ruby, which comes into its own in candlelight, is associated with passion, victory, charity and love.
Aluminum oxide. Hardness: 9. Its planet is Mars. Thailand, Cambodia, Sri Lanka, Madagascar, Kenya,Tanzania, Afghanistan.
A golden-yellow or red crystal, found as an inclusion in certain gems in the form of slender needles or fibers. Rutile can be seen in corundums, garnets and quartzes and often causes the optical phenomenon known as asterism.
Crystallized titanium dioxide. Hardness: 6 to 6.5.

A variety of corundum, as is the ruby, the sapphire is a rare precious stone whose blue color has always been associated with the sky, and by extension with heaven and religion.
Its name originates from a Sanskrit word (sauritatna) and it has been worshiped for thousands of years.
In Greece it was named hyakinthos after the blue iris, and was worn by priests to show their link with heaven. In the early thirteenth century a papal bull issued by Innocent III advised prelates to wear a sapphire on their right hand to symbolize the divine light they transmitted in their blessings.The intensity of a sapphire’s blue is determined by the amount of titanium oxide it contains.
Some of the finest specimens originate from Kashmir (a bright velvety blue), Burma (deep blue with a touch of indigo) and Sri Lanka, where two thirds of sapphires are mined and which vary from cornflower blue to sky blue with a hint of mauve.
Cartier has left its mark on the history of the sapphire thanks to the jeweler’s most loyal customers.
In 1949 Cartier created the legendary “panther” brooch, depicting a panther whose spotted coat is made from diamonds and one hundred and six sapphires atop a magnificent cabochon Kashmir sapphire weighing 152.35 carats.
Two years later, again for the Duchess of Windsor, Cartier mounted a 206.82 carat sapphire as a pendant.
The sapphire reveals the full extent of its beauty in daylight, and is dulled by electric light. It is said to protect travelers.Aluminum oxide. Hardness: 9. Birthstone of the month of September. Its planet is Jupiter. Symbol of serenity. Sri Lanka, Cambodia, Thailand, Madagascar, Tanzania, United States, Australia, India, Brazil.

The type of shell used since ancient times for its ornamental value is that of the marine turtle, now a protected species.
Once extremely common, objects made from genuine shell are now rare.
The most sought-after types of shell are translucent, yellow, brown or mottled.
Shell is often matched with precious stones in jewelry.
Having introduced shell headbands trimmed with pearls and diamonds in 1922, in 1937 Cartier created a sumptuous pale yellow shell comb for Barbara Hutton, set with baguette diamonds and presented in a matching shell case.Hardness: 2.5.
A more or less dense iridescent veil found in corundums and caused by the presence of slender rutile needles that intersect at an angle of sixty degrees.
A group of transparent stones of different colors, including peony-red, cherry-red, yellow, green and blue.
The most sought-after shade is cherry-red, whose resemblance to the ruby is such that it was often mistaken for the red corundum until the mid-nineteenth century.
The French even named it the “balas” ruby, after Balash in Afghanistan where such spinels were reputedly mined.
Poet Olivier de Magny (1529-1561) wrote these lines for his beloved, Louise Labé: "the two balas rubies of your tempting lips, and the sparkle of your eyes that slowly enchants me."
Most legendary “rubies” are in fact spinels: the Black Prince’s Ruby, part of the British crown jewels and weighing 170 carats; another weighing 414.30 carats that was set in the crown of Empress Catherine II of Russia and can now be seen in the armories museum in Moscow; and the 105-carat “Côte de Bretagne”, sculpted to resemble a dragon which was part of Duchess Anne of Brittany’s dowry.It can now be seen at the Louvre Museum in Paris.
Magnesium aluminate. Hardness: 8. Its planet is Saturn. Madagascar, Sri Lanka, Pakistan, Thailand, Afghanistan.
A large, usually flat facet surrounded by the star facets and which forms the uppermost surface of a cut stone.The eye is drawn into a cut stone through its table.
A transparent variety of zoisite that is an intense blue tinged with pink. When viewed in electric light its color takes on a more pronounced mauve hue, similar to that of certain sapphires.It was discovered in 1967 in Tanzania, and is still found only in this country. Silicate of calcium and aluminum. Hardness: 6.5.

At one time all yellow stones were called topazes, believed to come from a contraction of the Greek words topos and azos which can translate as “place without trees”, perhaps a reference to Zabarjad or Saint John's Island in the Red Sea. This gave rise to the common misconception that all topazes are yellow. In reality topazes come in all colors, of which the most precious is pink, although blue and green topazes are also highly prized.The most famous topaz, the Bragance (1,680 carats) which belongs to the Portuguese crown, is such a pale yellow as to be almost colorless and for a long time was mistakenly believed to be a diamond. Cartier began creating topaz jewelry in the 1920s then, in the 1930s, magnificent parures of necklace, earrings, bracelet and brooch using light and dark topazes, as well as head ornaments and necklaces in topaz and diamond. The topaz is reputed to ward off melancholy, bring wisdom and prevent its wearer from straying from the path of virtue. Fluosilicate of aluminum. Hardness: 8. Birthstone of the month of November.Its planet is Mercury. Symbol of wisdom. Brazil, United States, Russia, Sri Lanka.

This stone was introduced to Europe in the early eighteenth century by the Dutch, who discovered it in Ceylon. The Singhalese referred to it as oramalli, a word also used to describe zircons. The Dutch renamed it aschentrekker, meaning “ash puller” due to an unusual property with which pipe-smoking Dutch sailors were once familiar: when heated, tourmaline becomes electrically charged and thus attracts ash and dust. Dutch sailors used it to empty the ash from the bowl of their meerschaum pipes. No other gem comes in such a vast array of colors. Single-color tourmalines are rare. Most display a multitude of color nuances blending one into the other, or concentric colored layers. One such specimen is the famous watermelon tourmaline, which has a pink heart surrounded by green. The most coveted tourmaline--rubellite--is red, hence its name. King Gustav of Sweden presented Empress Catherine II of Russia with a rubellite weighing 250 carats, still conserved in the Diamond Fund in Moscow. The rarest, indicolite, is a deep blue-green. The most common color for a tourmaline is green. The muse’s stone, tourmaline is said to give wings to the artist’s imagination. Borosilicate of aluminum. Hardness: 7 to 7.5. Birthstone of the month of October.Symbol of creativity and inspiration. Afghanistan, Brazil, United States, Madagascar, Russia, Sri Lanka.

This blue stone has been admired and adopted for its beauty for thousands of years, as proven by the ruins of ancient turquoise mines in the Egyptian desert of Sinai (4,000 years BC).
At that time turquoise was used for personal adornment (necklaces and rings) and, sculpted into a beetle shape or engraved with ritual inscriptions, worn as a talisman. It was even ground into a powder and used as eye makeup.
First adopted by ancient civilizations, its intense color (which varies from sky blue to green-blue depending on the amount of iron and copper it contains) has never ceased to seduce populations throughout the world.
For over fifteen hundred years the finest specimens have been mined in the Nishapur region of Iran, from where they were exported to Europe, India and Arabia, often via Turkey from which it took its name.
Other turquoise mines were exploited in Tibet, China, Mexico and North America. Nineteenth-century Europe, inspired by the Romantic movement then by Art Nouveau, adored the turquoise. The Art Deco style made particular use of matrix turquoise, which is crisscrossed with brown (limonite) or black (jasper) veins.
Turquoise entered into the subtle color combinations created by Cartier for its Egyptian-style creations in the 1910s, when it was matched with lapis-lazuli for contrasting shades of blue, then again in the 1920s for the jeweler's Art Deco-style creations, when Cartier took its favorite color combination of green and blue to new heights using turquoise, blue enamel, jade and lapis. Hydrous basic phosphate of aluminum, copper and iron. Hardness: 5.5 to 6. Birthstone of the month of December. Its planet is Mercury. Brazil, Chile, China, Iran, Mexico, Peru, Tibet.
An inclusion evoking such a form and a characteristic of certain sapphires, particularly those from Ceylon (Sri Lanka).