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June - Pearl / Alexandrite

Pearls

The pearl was the favored gem of the wealthy during the time of the Roman Empire. This intriguing gift from the sea had been brought back from the Orient by the Crusaders. Roman women wore pearls to bed so they could be reminded of their wealth immediately upon awakening. Pearls were once considered an exclusive privilege for royalty. A law of 1612 drawn up by the Duke of Saxony prohibited the wearing of pearls by nobility, professors, doctors or their wives.

An old Arab legend tells us that pearls were formed when dew drops filled with moonlight fell into the ocean and were swallowed by oysters. The modern scientific explanation is not nearly as romantic but still quite fascinating.

A natural pearl (often called an Oriental pearl) forms when an irritant works its way into a particular species of oyster, mussel or clam. As a defense mechanism, the mollusk secretes a fluid to coat the irritant. Layer upon layer of this coating is deposited on the irritant until a lustrous pearl is formed. A cultured pearl undergoes the same process. The only difference is that the irritant is a surgically-implanted mother-of-pearl bead or piece of shell. The core is, therefore, much larger than in a natural pearl. As long as there are enough layers of nacre to result in a beautiful, gem-quality pearl, the size of the nucleus is of no importance to beauty or durability.

Imitation pearls are a different story altogether. In most cases, a glass bead is dipped into a solution made from fish scales. This coating is thin and may eventually wear off. The island of Mallorca is known for its imitation pearl industry.

On the other side of the world, pearls were being worn for adornment by the American Indians. The freshwater pearls of the Mississippi River were strung into necklaces, sewn onto headdresses and set into copper ornaments. Freshwater pearls occur naturally and are generally very irregular in shape, with a puffed rice appearance being the most common. San Angelo, Texas in the late 1800's was known as the Freshwater Pearl Capital of the US. Even today the numerous lakes in this region yield fine freshwater Pearls.

Fine natural pearls are quite rare. The Persian Gulf has always been the source of the finest natural saltwater pearls. Other sources are the waters around Sri Lanka, Australia, Japan, Mexico, Panama, Venezuela and the Micronesian Islands.

One of the largest saltwater pearls still in existence is the Hope Pearl, first acquired by Henry Philip Hope in the 19th century. It is two inches long, and varies between 31/4 and 41/2 inches in circumference. It is on display at the British Museum of Natural History. Most saltwater Pearls now come from Tahiti and are known as South Sea Pearls. The nuclei begins larger (at least 8 mm) yield natural Pearls in the 10-15 mm size.

Japan and China are major source of cultured freshwater pearls. The smaller nuclei and growth periods less than 8 years yield smaller Pearls in the 2.5 to 8 mm range. Above that the retail prices soar to several hundred dollars for 8.5, 9.0 or 10.0 mm fine White Pearls.

Mohs hardness: 2.5 to 4.5


Alexandrite

One of the most interesting, yet least known, of the important gemstones, Chrysoberyl deserves a special recognition for its rarity and astounding beauty. The rare presence of chrome traces turns Chrysoberyl into Alexandrite. The stone was named after Czar Alexander II of Russia. Alexandrite changes color from soft green in sunlight to deep red in candle or artificial light. The composition is the same as Beryl, but the distinct pleochroism shows deep red, orange-yellow and green colors. Because of the chromium in Alexandrite it may fluoresce a dull red in short-wave and long wave UV.

SOURCES:
Russia:
Has long been the most desirable source for gem Alexandrite. The finest comes from the Takowaja emerald mines in the Ural mountains. This is where it was discovered in 1830.

Brazil:
Alexandrite from Brazil is mined in the States of Minas Gerais and Bahia. Until the discovery of its new Alexandrite vein, Brazil commanded little or no respect as an Alexandrite producer. At present all major Brazilian mines are under government control. Recent finds have led to a great deal of infighting between mine owners. The "wars" became so violent that the government trenched a moat around and posted soldiers upon, the only remaining operating mine. For prized stones, the trade counts on Sri Lanka, but only on a sporadic basis. These stones always seem to have an undertone of brown or yellow. Seldom do you see the fine 100% color change exhibited in the new Brazil or old Russian material. Sri Lankan material can often exceed 20 cts in size and be extremely clean. But the faint orange color change usually can only be seen in laboratory conditions. Nobody knows how much material from the new Brazilian find has been cut. But insiders estimates range from 5,000 to 10,000 carats. These stones boast admirable color purity and richness. The completeness of the color change in most of the material is one of the most amazing things about the new find.

Nigeria:
This new source of Alexandrite is yielding beautiful Blue Green material with much better clarity than the Brazilian material. However, the color change is more to an orangish pink color rather than rose or red.

CLARITY:
Alexandrite is a TYPE III gemstone as classified by the Gem Institute of America. That means you can expect Alexandrite to have numerous and eye visible inclusions. The stone pictured about would be considered very clean even though you can easily see the inclusions with your naked eye.

PRICE & SIZE:
As of May 2005, fine quality, nearly eye clean, 2-to-3 carat Brazilian stones were already commanding prices of $20,000 to $35,000 per carat. Although 30 to 40 carat Russian Alexandrites are known to exist, most are around 8 carat and you rarely see Siberian stones that have the right color and purity. These stones can fetch upwards of $50,000 per carat. One should not forget that the primary buyers of Alexandrite for some time now have been the Japanese. Especially fond of sizes between 2 and 4 carats, they have so far swallowed prices exceeding $25,000 per carat. Click here for our current price guide.

CUT:
The nature of the Alexandrite crystal and its unique trichoric phenomenon dictates the rough will be cut for purity, color change, and size. Stones are not cut to "calibrated" size, nor seldom is the rough wasted to cut stones over 5 mm round. Pearshape, princess, trillions, emerald-cut, or marquette shapes likewise are not the shape of choice to which Alexandrite is fashioned. Rather the antique or cushion shape, small rounds under 3 mm or elongated ovals dominate the finished supply.

How to Care for Alexandrite
Alexandrite is rated “excellent” for everyday wear however one must still use caution and protect it from harsh chemicals, extreme temperatures and scratches. The best way to clean the stone is with mild dish soap and warm water, using a soft toothbrush.

Mohs hardness: 8.5





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