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 Post subject: opal play of color to produce a cat's eye effect
PostPosted: Thu Feb 13, 2014 12:58 pm 
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Has any one done any research in what causes the play of color to produce a true cat's eye effect(chatoyance line ) in precious opal with no evidence of any fibers being present under high magnification.


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 Post subject: Re: opal play of color to produce a cat's eye effect
PostPosted: Fri Feb 14, 2014 11:16 am 
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Can you post a picture?


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 Post subject: Re: opal play of color to produce a cat's eye effect
PostPosted: Sat Feb 15, 2014 12:01 pm 
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Here is sample image of one of two opals that were examined.
sample seen here there are no fibers associated with the catoyance that can be seen -neither the start nor the end of a single fiber could be identified. The fire in the eye penetrated down into the body of the opal similar to seeing rain falling at a slight angle


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 Post subject: Re: opal play of color to produce a cat's eye effect
PostPosted: Sun Feb 22, 2015 7:53 pm 
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I think it is very rare that a stone could display cat's eye effect without the presence of fibrous or needle-like inclusions.


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 Post subject: Re: opal play of color to produce a cat's eye effect
PostPosted: Mon Feb 23, 2015 6:33 pm 
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I have seen some like this from Idaho. Also a "star" which consists of 6 points of light, alternating in color red blue and green. Don't know what causes it though.


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 Post subject: Re: opal play of color to produce a cat's eye effect
PostPosted: Mon Feb 23, 2015 6:56 pm 
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This effect is found in Australian opal.
I have seen Lightning ridge "jelly", with "aurora" like veils, drifting thru the gem.
Also have seen "cats eye effect".
Ross Sedawie, a forum member, is an opal expert, he may have some photos to share?
You must remember how some opals are formed, liquids permeating the sandstone, for example, and so layers of colour are easy for nature to lay down.
Barry.


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