National Shutdowns have put the lid on most shows.
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PostPosted: Wed Mar 01, 2006 1:45 pm 
Platinum Member

Joined: Sun Oct 16, 2005 12:42 pm
Posts: 2591
Excellent article Vincent and great pictures as usual.
Reminds me to use the fiberoptic lightning more often.

Thanks for all the time and deprived sleep you put in your research

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PostPosted: Thu Mar 02, 2006 11:11 am 
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Joined: Mon Oct 17, 2005 1:06 pm
Posts: 718
Location: Bangkok, Thailand
Yes Doos,

Fiber optics illumination is the type of lighting we are using the most at AIGS lab (and also to my knowledge in many other labs).
I usually recommend to start the examination of gemstones with the naked eye for few seconds. Then using microscope with dark field illumination also for a few seconds. After that a carefull axamination with fiber optics is a key.
After that we can move to some examination bright field illumination under cross polars or immersion or both... other type of examination like shadowing, bright field or overhead lighting can be also used if necessary but are less useful.
Nevertheless, the key to properly use a gemological microscope is to examine the stone in all directions using all the different lighting environments you can. As each type of lighting environment has strong and weak points, this is the best technique to optimize the use of a gemological microscope.

All the best,

Vincent Pardieu

The views expressed here are V. Pardieu’s opinions and do not necessarily reflect those of GIA Laboratory Bangkok ( he is an employee since Dec 2008.

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PostPosted: Thu Mar 02, 2006 11:55 am 
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Joined: Tue Nov 29, 2005 2:02 pm
Posts: 2647
Hi Vincent,
I just wanted to say a thank-you too for all of your hard work and for taking time to keep us informed.
We appreciate your level headed approach to this research and your efforts to prevent any panic or false assumptions until the results of your work can identify exactly what is happening with the BE treatments and the extent of it's effect in the trade.
Often rumors and inuendo does more damage than the actual act. The gem industry relies heavliy on trust from the miner to dealer to vendor all the way through the food chain. That's why it's imperative that we understand fully how these suspect treatments come about. Whether on pupose or by accident the trickle down effect can disrupt an entire market segment. A steady hand is needed to keep things in perspective.
I would like to believe the majority of burners understand that any undisclosed treatments could damage a sensitive market and eventually destroy their own livelihood, at least in the short term.
Let's hope if this or any new treatment becomes routine in the corundum market and establishes itself as an alternative to other accepted treatments, that it will be done with the cooperation and full disclosure of the burners who chose these treatment methods.
But of course we just don't know that yet.

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