Chatoyancy in Gemstones

by NASRINA PARVIN KHAN

Inclusions of foreign particles in gems are the main reason of reflection of light and create the phenomenon "chatoyancy". The reflective inclusions of fibrous particles of foreign minerals in gems should be thin, needle-like parallel orientation. Sometimes occurrence of hollow tubes in parallel orientation is the reason of silky radiance of gems, which known as "chatoyancy".

Chatoyancy in Gemstones @ Jewel Info 4 U

By: NASRINA PARVIN KHAN

"Chatoyancy" is a special optical phenomenon, which is exhibit by some rare gemstones. This uncommon and excellent phenomenon helps to create attraction and adds value to a gem. This phenomenon is a particular property of reflecting light because of fine inclusions of some foreign minerals in gems.

Due to the reflection of light the phenomenon "chatoyancy" took form .The reflection exhibits a single glowing band of light across the surface of a gemstone and helps us to see a silky glow, which called chatoyancy. The displayed band of light looks like a slit of an eye. A finely marked eye line can be recognized, which runs right through the gem. In case of some good specimens, the eye seems to open and close when the gem is rotated.

The term "chatoyancy" comes from the French "chat", which means cat and "oeil", which means eye. So, the term "chatoyancy" literally translates as "the eye of a cat". For this reason, this phenomenon is also known as cat's eye effect.

The magical phenomenon "chatoyancy" most commonly has been seen in quartz. Sometimes it can be seen in tourmaline, moonstone, tiger's eye, corundum and several minerals. This phenomenon is very very rarely seen in beryl especially in emerald, which comes from Brazil and Colombia. Others "chatoyance" as well as cat's eye gemstone are found in SriLanka, Tanzania, Brazil, China and Russia.

Usually, "chatoyancy" or cat's eye gems refer to stones, which exhibit the special optical phenomenon "chatoyancy". But the term cat's eye should always use with a mineral species or a gem name as a modifier, such as cat's eye tourmaline, cat's eye moonstone or cat's eye Chrysoberyl. But the most beautiful, valuable and miraculous cat's eye gem is cat's eye Chrysoberyl. So, the simple term cat's eye used to refer to the stone Chrysoberyl, traditionally. It has given this honor for its magical chatoyance effect. Cat's eye on the surface of the Chrysoberyl winks like the eye of a cat.

Inclusions of foreign particles in gems are the main reason of reflection of light and create the phenomenon "chatoyancy". The reflective inclusions of fibrous particles of foreign minerals in gems should be thin, needle-like parallel orientation. Sometimes occurrence of hollow tubes in parallel orientation is the reason of silky radiance of gems, which known as "chatoyancy". There is another factor also. The inclusions of cat's eye gems are not well organized, scattered randomly.

The silky radiance produce when the cat's eye band perpendicular to the needle .To Display the 'chatoyancy' or cat's eye, the gems must be cut in a tall, domed shape, which called as cabochon.

'Chatoyance' or cat's eye gems are transparent to opaque. The special optical phenomenon 'chatoyancy' seems to glide magically across the surface of a gem, when it is moved. Gems that produce 'chatoyancy' allow the cosmic color to pass through it and create a magical effect.


'Chatoyancy' or cat's eye is best esteemed under sunlight or other point light source; like a spotlight or penlight. Multiple light source or dimly lit do not help to create the phenomenon ''chatoyancy' with magical effect. Each of multiple light source produce a cat's eye on the surface of the gems and give an unfocussed look. In a cloudy day or under florescent lights 'chatoyancy' or cat's eye may vanish completely.

A strong, well entered and straight eye produce in fine quality gems. A strong eye produced by over headed light. On the other hand a one-side moving light source help the gem to get the lighting laterally and creates "milk and honey" effect. "Milk and honey" effect refers to one side light and one side dark effect. When two light source used to move from the center to the side the eye splited into two bands. Each band follows one of the light sources and creates an effect of opening and closing.

'Chatoyancy' or cat's eye gems have a distinct place in Astrology. It is believed that it has healing powers. These gems protect the wearer from all the types of mysterious dangers and disease and brings good-luck to the wearer. It also promotes concentration and the learning ability, tolerance and harmony.

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