Post subject: how to separate heated and unheated blue sapphire ??
Posted: Thu Jul 29, 2010 11:24 am
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How to separated natural heated & unheated blue sapphire if there is only fingerprint ?? please explain how is different between fingerprint and feather.
Post subject: Re: how to separate heated and unheated blue sapphire ??
Posted: Thu Jul 29, 2010 1:17 pm
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Joined: Thu Jan 05, 2006 4:27 pm Posts: 1750
Hi jpanp,
Fingerprint and feather are indeed words describing the same thing. Properly called a partially healed fractures.
Heated and unheated sapphires are usually seperated by careful observasion with a gem microscope. There are various pointers to heating. broken rutile needles, fractures around crystal inclusions etc.
You say the only thing in the stone is a fingerprint. Are you sure there are no other inclusions? fingerprints / feathers / veils etc are also inclusions in synthetic flux grown sapphires where they are known as flux veils. These are generally opaque (yellow or orange) where natural veils are transparent to transluscent.
If there are NO other inclusions than the veil then I'd cheque extra carefully to ensure it isn't a flux synthetic.
other than that maybe more magnification and morecareful obsevations. Very few natural corundums have no inclusions in them.
Hi Japnp, I would say your stone is likely to be flux synthetic as Frank pointed out. Many compnies such as Ramaura, Chatham produce flux grown synthetic sapphires. Such stones can be only confirmed to be natural if u put it under advanced instuments such as the FTIR spectrometer etc. However what I have usually seen in feathers in natural sapphires is randomly oriented liquid droplets which after heating usually look somewhat aligned. However this is not a sure-shot factor of identification and u have to rely on Zircon inclusions or undissolved rutile silk or sometimes two-phase inclusion to identify it as natural unheated stone. I think the best thing for you to do would be to submit the stone in a recognised lab such as AIGS or GIA. If you do not want to spend too much I think an AIGS e-certificate would be best option for you.
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