Chrysoberyl Cat’s Eye Gemstone.

Posted by slang on September 7, 2009

The most famous and valuable cat’s eye gemstone is chrysoberyl cat’s eye. The cat’s eye can fetched very high premium with its vivid cat’s eye effect. In fact, some of the prices of the chrysoberyl cat’s eye are comparable to the prices rivaling high quality sapphire.

Interestingly when cat’s eye is mentioned amongst jewelers, they normally mean the Chrysoberyl cat’s eye. Other types of cat’s eye gems require an designation like cat’s eye apatite, cat’s eye quartz and others.

Many would wonder the reasons for the sought after chrysoberyl instead of other types of cat’s eyes. The reasons are as follows:

• Chrysoberyl has superb gemstone characteristics, with a hardness of 8.5 on the Mohs scale. This places chrysoberyl right behind ruby and sapphire as an especially hard-wearing gem, suitable for all kinds of jewelry. Because of its excellent hardness, chrysoberyl takes a good polish and displays superb luster.
• Chrysoberyl cat’s eye displays a very sharp cat’s eye that can be seen in any kind of light. Some other gem varieties that exhibit phenomena such as the cat’s eye or star effect do so only when strong light is focused on the stone.
• Some chrysoberyl cat’s eyes also have a considerable degree of translucency, rarely found in gems cut as cabochons.

More details  of Chrysoberyl:

• Chrysoberyl was discovered in 1789 and described and named by Abraham Gottlob Werner, in 1790. Werner worked at the Freiberg School of Mining from 1790-1793 and was well known as one of the most outstanding geologists of his time.
• Chrysoberyl is usually found in golden-yellow, green-yellow, brownish or red tones. The main deposits are in Brazil, Sri Lanka, Burma, Madagascar, Russia, Zimbabwe and the USA.
• Incidentally, there is another chrysoberyl which is the Alexandrite, chrysoberyl cat’s eye which is quite rare and exotic.

Scapolite Cat’s Eye Gemstone

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Scapolite, which is Greek for “rod” or “shaft,” is commonly found in stubby to long prismatic crystals, hence the name. Its crystals are tetragonal so that it will commonly have a square or octahedral cross-section. It was was first discovered in 1913 in the Mogok Stone Tract in upper Burma. {See its gemological properties below.}

Scapolite usually exhibits excellent transparency and been known for its gemstone quality. Some of the less transparent material exhibit chatoyancy or the cat’s eye effect when cut as cabochons. Cat’s eye stones are rather rare and desirable as they tend to have exceptionally sharp eyes. 

Cat’s Eye Apatite

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Apatite gets its name from the Greek word for “cheat”. The care for apatite should be quite careful as it is similar to that of opals which is heat and shock sensitive, so steamers and ultrasonic must be avoided. The stone is slightly too soft to recommend for rings. Cat’s eye apatite is generally untreated.

Like other selection of the cat’s eyes gemstone, look at :

• Chatoyancy’s effect.

              When the stone is rotated, the cat’s eye glides over the surface. 

• Clarity
  Apatite is usually a transparent gemstone. 
• Cut
  The cabochon cut is excellent for a unique brooch or pendant, if its base is parallel to the fibers.

Quartz Cat’s eye

Posted by slang on September 6, 2009

Quartz cat’s eye is quartz in which inclusions of rutile create chatoyancy or the cat’s eye effect. Usually found in colors of white, green, yellow or brown, quartz cat’s eye is a durable gem which is a inexpensive alternative to chrysoberyl cat’s eye. Deposits are found in Sri Lanka, Brazil and India

Sillimanite Cat’s Eye

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Sillimanite is an aluminum silicate, related to both andalusite and kyanite. In fact these three minerals are polymorphs — they share the same chemical composition but different crystal structures.

Sillimanite is named after the American chemist Benjamin Silliman (1779-1864). Silliman was one of the first American professors of science and taught at Yale University.