Colored Stones

Stones and Natural Materials used in Jewelry

Ruby
Sapphire
Emerald
Amethyst
Citrine
Aquamarine
Jade
Topaz
Opal
Lapis Lazuli
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Natural materials
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Pearl
Amber
Jet
Coral

More Info

Stone History
Stone Science
Diamonds
Colored Stones
The 4 "C's"

RUBY
The ruby owes its color and its exceptional rarity to a trace of chromium which settled into he mineral during the crystallization of the ruby substance. As a rule chromium appears regularly, but sparsely, only in the deeper levels of the earth. Only the rare occasions when chromium rose to higher levels and combined with aluminum oxide could produce the most precious red corundum known as the ruby. Its delicate color graduations in all shades of red are universally admired. Because the mining of this stone is also extraordinarily difficult, the ruby is rightly ranked among the great treasures of the mineral kingdom.

The most beautiful rubies come from the almost inaccessible high Mogok valley in Burma. To this day, native families working in teams, sift the soil laboriously hacked out and dug by hand, and when possible, sieve it through water. This is the site of the most coveted, rarest and most valuable color variant, the most famous carmine red known as "pigeon´s blood." Other shades of red are typical of other deposits in Thailand, Sri Lanka, Cambodia, Tanzania, Afghanistan and North Carolina (USA). But the color alone is not sufficient to identify the source because all the sites where rubies are found yield rare as well as more common colors.

To determine the origin and authenticity, the experts prefer to rely on the pattern of inclusions rather than color. Rubies without any inclusions are extremely rare; almost all contain tiny crystals of foreign matter. Their nature allows the gemologist to make deductions. So-called silk in corundum is a typical example. It is a delicate glittering silvery web of beryl fine rutile needles which may be concentrated into a star when the surface is cut in a domed shape.

Large ruby crystals are extremely rare, much rarer than large diamond crystals and much less frequent than large crystals of there varieties of corundum. The largest known star ruby, the size of a walnut, weighs 138 carats. The stone is known as the Tosser Reeves Ruby and is on display at the Smithsonian Institution in Washington, DC (USA). The largest known ruby is in the Russian Imperial Crown. The second largest so-called ruby (is actually a spinel and not a ruby) is the world famous Timur Ruby, 352.7 carats. It is in the private collection of Queen Elizabeth of England.

The British Imperial State Crown and that of Elizabeth, the Queen Mother bears some of the most famous stones in history.

Mounted at the center of the cross above the Imperial State Crown is the sapphire which adorned the finger of Edward the Confessor at his coronation in 1042. It is the oldest jewel in the treasure of England.

Beneath the sapphire is a splendid red spinel, which is known as the "Black Prince´s Ruby." It was described among the treasures of the King of Granada assassinated in 1367 by Peter the Cruel, King of Castille. This Peter presented the stone in token of his recognition of Edward Prince of Wales, the Black Prince. Later the life of Henry IV was saved by the solidity of this stone. It withstood the furious sword blow which the Duke of Alencon delivered to the king's helmet at the battle of Agincourt. Below the spinel, the large diamond is the second largest stone cut from the Cullinan. It weighs 317 carats.

SAPPHIRE
Like the ruby, the sapphire is also an aluminum oxide. Rubies and sapphires constitute the gemstone family of corundum. All colored corundums except the red (ruby) are called sapphires. Sapphires occur in a wealth of magnificent color, but the most widespread and best known is the blue. A deep cornflower blue variety is by far the most popular, the rest and the most valuable.

Thus the sole difference between ruby and sapphire is in color. As chromium is the cause of the red shades in ruby, titanium and iron re responsible for the innumerable blue variants in sapphire. Sapphire is less rare then ruby because iron and titanium occur more frequently than chromium at the higher levels of the earth. In all other ways, sapphire shares the properties of the ruby, especially by the measure of its hardness of 9, the basis of its durability, as well as its high refraction, the cause of its intense sparkle. Sapphires, like rubies, are distinguished by their inclusions, the formation of star stones is also frequent and typical.

Sapphire deposits are found in Sri Lanka, Burma, Thailand, Tanzania, Cambodia, Australia, and the United States. Like the ruby, certain shades of blue are typical of sapphires found in particular localities.

The ancients already collected the cherished sapphire, royal treasuries competed for their possession, and a Papal Bull went so far as to give approval to the general veneration of the blue gemstone. Pope Innocent III decreed that every bishop and every cardinal must wear a sapphire on his right hand, with which he bestowed blessings.

EMERALD
The oldest known emerald mine is in Sabara in Upper Egypt. It was worked by the Ancient Romans. Recent discoveries determined that some emeralds previously thought to have been mined in antiquity in the Near East were actually mined in Columbia, South America. Which in itself raises the issue of how they found their way from South America to Europe.

The green of the emerald is incomparable in its beauty and depth. From pale leaf green to a subdued pine-green, this most precious representative of the beryl group exists in a wide range of tones. The rarest and most valuable color is the dewy green of new spring grass. The fact is that the basic material of all beryls, a beryllium-aluminum silicate, is completely colorless in its natural state. Only a trace of chromium is sufficient to give emerald its color and thereby its unique beauty and pride of place, not only in the beryl family, but in the whole realm of colored gemstones.

Emeralds are very rarely completely free of inclusions. Liquid-or gas filled cavities and mineral inclusions combine to make that garden known as jardin, of green tendrils, leaves and branches within a cut emerald which makes each stone so different. A look through the gem microscope into the interior of an emerald is therefore always an exciting spectacle, one which allows the expert to gain some knowledge about the nature and the origin of the stone.

The most important sites are found in Columbia, where some of the deposits were used by the Inca, then lost over time. Emeralds of commercial quality are also found in Rhodesia, South Africa and Brazil.

In contrast to the diamond, the cut of an emerald is not usually designed to bring out the most intense "fire" (to direct the rays of light within the stone so as to reflect the maximum amount of light). Rather, the cut should allow the viewer to enjoy the intense green color and to look into the stone´s interior. Consequently, the common emerald cut is designed to show the "garden" of inclusions to best advantage.

AMETHYST
This gem's color runs from lilac to deep purple quartz. It is the most valuable member of the quartz stones. The stone's name is derived from the Greek word amethystos, which means "not drunk" for in ancient times, it was thought to prevent intoxication as well as to cure disease, and protect a wearer with its mystical powers. The deeper the color, the more valuable the stone. Iron causes the color of amethysts, however, when nature heats amethyst to over 550°C, the resulting stone is a citrine.

CITRINE
The citrine is basically the same stone as an amethyst, but a deep rich golden color. It is found together with amethysts, but it is much less common than an amethyst. Good stones are very rare and potentially more valuable than an amethyst. However, most of the stones on the market are heat treated low-grade amethysts.

AQUAMARINE
The aquamarine is a lovely blue to blue-green beryl, but is known under different names for different colors: morganite is pink, heliodor is golden yellow; there are also colorless, pale green and yellowish green beryls. Gems are found in pegmatites and adjacent to granites, particularly in zones of metamorphic limestones. They are produced principally by Brazil and in regions of Minas Gerais and Bahia. Crystals weighing 20 kilos or more have yielded huge cut stones. The aquamarines found in the Ural mountains are a very beautiful blue; those found in Madagascar are light pink to violet pink morganites. Mozambique is known for fine beryls as well as tourmalines.

JADE
Jade is a name given to a group of silicates with an opaque waxy, microcrystalline structure. There are two minerals which comprise true jade: jadeite, sodium aluminum silicate and nephrite, a complex hydrous silicate containing calcium, magnesium and iron, and closely related chemically and geologically to asbestos. Jadeite can be white, green, pink, mauve or brown. Particularly sought after is the emerald-green variety also known as Imperial Jade. It is found in the thin seams of serpentine rocks. Nephrite can be white, gray, a wide range of greens, and sometimes, pink. It can also be found in serpentine rocks, or in metamorphic schists. Chloromelanite is a variety of jadeite which is nearly black due to the inclusion of iron; chromojadite contains chromium.

Jades were carved by neolithic man, and in China, beautiful objects have been made in jade for over 4,000 years. To many, jade is more precious than diamonds or gold. It is believed to protect health and bestow immortality on the wearer. To reap its benefits, one can wear jade, display jade carvings, or simply carry it in a pocket.

TOPAZ
Topaz is found as large fine stones which may be colorless, blue, yellow or orange. Pink stones are almost always produced by "firing" or heat treating the stone to change its color. Topaz occurs in acid igneous rocks in Brazil, Siberia and the USA. Topaz crystals can be huge, some weighing over 100 kilograms. In ancient times, the topaz was frequently confused with the citrine (a fired citrine is an amethyst whose color has been changed to yellow-orange by heat treatment).

OPAL
Opals are a hydrated form of silicon oxide with an amorphous structure. One of the most beautiful gems, the opal is translucent and bathed in a milky light or `opalescence´ shot with lively spectral colors. This opalescence is caused by the many changes of refractive index produced by the thin layers of stone and air, and according to the angle of the cross-section. The colors can range from white, orange and red to dark blue (black opal).

Opal however is a brittle and soft mineral that is prone to dehydration and cracking. It does not have a crystalline structure, rather it is one of the few amorphous mineraloids. Opal is actually a mineral gel.

The finest opals come from Australia, Hungary and Mexico. The rare black opal is mined in Australia and Nevada. The volcanic fields of Mexican produce the fire opal has a red or orange color. Opals can be found as nodules or incrustations in volcanic rocks such as andesite or trachyte.

LAPIS LAZULI
A rich gold veined dark blue stone, Lapis Lazuli is formed from many minerals principally lazurite but also minerals such as sodalite and hauynite and calcite or pyrite. Known and sought out for at least 6,000 years because of its rich blue color, lapis lazuli occurs rarely in masses of any importance. The oldest known source is in Afghanistan, where the mineral occurs in a marble inclusion in a metamorphic rock. Other localities in which lapis lazuli suitable for ornamentation is found include a site near Lake Baikal in Russia, the province of Coquimbo in Chile, and in California.

PEARL
Unlike a gemstone, which needs skillful cutting to bring out its brilliance and sparkle, a pearl does not need the human touch to achieve its full beauty. It is a finished jewel in its natural state, noble, enticing and mysterious. The prices of fine (non-cultured) pearls can match those of precious stones.

The Pellegrina pearl weighs 3.2 ounces. It has such a delicate shimmer as to seem almost transparent. It was owned by Philip II of Spain and later by Louis XIV; acquired in 1826 by Princess Tatiana Youssoupoff, it was subsequently presented to the Zosima museum in Moscow.
A more varied history belongs the the drop-shaped Peregrina, the "Incomparable" which weighs 7.1 ounces. It was found in 1550 by a slave on the coast of Panama and appeared in paintings by famous artists as it adorned several Spanish queens. It was purchased in the 1970´s by Richard Burton for Elizabeth Taylor.

The pages of history are filled with numerous myths and legends to account for the miracle of pearls. Ancient Indian myths trace the pearl's origin back to the clouds. Pearls were said to have descended from them into the depth of the sea on the far horizon, where the sky and the water touch. The Persian poet Saadi tells of a droplet of rain which, falling into the sea, humbly accepted its fate of geeing mingled with the ocean, for this it was laid by Aphrodite in a shell and there became a pearl. At the full of the moon, so says a Japanese legend the tears of the Queen of the Night fell into the green waters of Tatoky and were changed into pearls. An old Hebrew legend speaks of pearls as the tears shed by Eve when she was turned out of Eden. On his third Atlantic crossing while rounding the island of Trinidad toward the mouth of the Orinoco, Columbus saw half-open oysters hanging on the mangrove roots at low tide and thought the pearls were torpid dewdrops.

Science on the other hand, sees pearls as organically developing over a period of from 3-50 years in the living body of a mollusk hidden within the protective shell. The idea that a pearl grows around a grain of sand in the shell is contradicted by the fact that in hundreds of scientifically examined and millions of drilled pearls, no grain of sand has ever been found.

Rather, the result of an irritation of the shell-building skin, or epithelium, a single-cell membrane that surrounds the animal's body beneath the shell - a cyst forms by intensive multiplication of cells. In this so-called pearl sack, the pear is formed by the secretion of shell-building substances (cochiolin and calcium carbonate). Spherical pearls are purely accidental. In the particular process pearls are built up in domed layers. The layers, consisting of minute platelets of mother-of-pearl (aragonite - the orthorhombic modification of calcium carbonate), are cemented together by cochiolin, a horny substance similar to that of fingernails. These platelets slightly overlap. This overlap cannot be detected wither by the naked eye o the magnifying glass. It can be seen only under a microscope. But the light is reflected, diffracted and refracted a thousand fold in this structure. This causes the gem to shimmer with a delicate silken sheen and to glow as if lit from within. Since a oyster can live for over 200 years, the frown of a pearl may continue from 20-50 years. The same process can be repeated in one and the same shell. Some pearls can grow to the size of a pigeon's egg, and occasionally dozens of pearls are found in a single shell.

Besides the shape, color and size, the optical surface characteristics, luster and orient, determine a pearl's value. Luster is the unique pearly sheen of its "bloom" (skin), while the simmering iridescence, seemingly projected from within, is termed orient. These two features also help to distinguish the precious natural pearl from its imitation, for imitation pearls cannot attain either luster or orient in their highest form. These are exactly the qualities that have made pearls world famous. Pearls are not only found in salt water, but streams and rivers offer charming freshwater pearls whose pastel-shaded bloom is very attractive.

AMBER
Amber is a fossil resin, yellow to yellowish-brown, greenish yellow or reddish. It is not a mineral at all, but vegetable in origin. It's a tree resin. It is notable for its very low density, being only slightly heavier than water. Organic and inorganic material may be encased in the resin. Orgainc matter can be part vegetable (carbonized wood, and needles) and animal (ants, moths, flies, spiders, snails and other small organisms). Nowdays amber is mostly used for jewelry and personal items, but in the past it was used to manufacture articles for smokers (cigar and cigarette holders and mouthpieces for pipes).

One of the most extraordinary uses of amber is the exquisite Amber Room made of several tons of the golden tree resin - the lightest gem in the world. The room, often referred to as the "Eighth Wonder of the World," consisted of a series of large wall panels inlaid with several tons of masterfully carved high-quality amber, long wall mirrors and four Florentine mosaics.

Originally started in 1707 by the King of Prussia, the amber room was never completed by him, rather it's pieces remained in storage until King Friedrich Wilhelm the 1st gave all of wall sections to the Russian Emperor Peter the 1st as a diplomatic gift. Eventually the Amber Room was open in 1746 in The Winter Palace, where it was housed till 1755; that year it was moved to the summer residence of the Russian Emperors at Tsarskoe Syolo. It decorated the Catherine Palace, near St Petersburg, until September 1941 when invading German troops stripped the walls, packed the pieces into crates and carried it off to Königsberg in East Prussia (now the Russian city of Kaliningrad). As late as April 1945, the Amber Room was known to have been mounted as an exhibit in Königsberg Castle. It has not been seen since.

In the early 1980s, serious work on recreating the Amber Room based on old photographs and reminiscences was undertaken in the Catherine Palace, and completed in 2003. Read more about the Amber Room on MSNBC, and in the new book The Amber Room: Uncovering the Fate of the World's Greatest Lost Treasure, by Adrian Levy and Catherine Scott-Clark.

Amber becomes electrically charged on rubbing and burns with a pleasant smell.The Greeks noticed the static electricity effect on cloth air and fur and called amber electron. The word for electricity is derived from this term.

JET
Very popular in the late 1700's and early 1900's, jet is fossilized wood related to coal. It was highly prized for the fine black sheen it has when polished, and was used to create a variety of personal items from hair combs, shoe buckles to elaborate necklaces, and other items such as rosaries, snuff-boxes, ink stands, candlesticks and walking stick handles. In the 1800's jet was often used for mourning ornaments.

CORAL
The chalky skeleton of the coral polyps (colonies of tiny animals which proliferate in temperate and warm seas at depths between 50 and 200 meters) the color of coral can run from white to blood red. Rose colored and red corals have been used for a very long time in ornament, and statues carved from large pieces of coral are very valuable.