January 24 Through February 4—TUCSON, ARIZONA: Annual show
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Thu Mar 28, 2024 3:04 pm

All times are UTC - 4 hours




Post new topic Reply to topic  [ 5 posts ] 
Author Message
 Post subject: Views on Gem Tester instruments
PostPosted: Wed Jan 29, 2014 11:21 am 
Offline
Active Member

Joined: Tue Aug 23, 2011 12:51 pm
Posts: 80
Hi all:

Wondering what people think of instruments such as the Presidium Gem Tester, which supposedly separates many gemstones based on thermal conductivity.

It's frustrating not to be able to test small or inaccessible gems when they are set in a piece -- meaning I can't get a gem surface onto the refractometer. Often they are small or awkwardly located so it's also hard to see the inclusions clearly.

I guess this is where a gem tester would come in, but I've never used one. Love to hear thoughts on these gadgets.

Thanks,

Neil


Top
 Profile  
Reply with quote  
 Post subject: Re: Views on Gem Tester instruments
PostPosted: Wed Jan 29, 2014 11:27 am 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 21602
Location: San Francisco
Hi NeilS.
If you search our forum for reflectometers, like the Presidium, you will see that we have found them unreliable.


Top
 Profile  
Reply with quote  
 Post subject: Re: Views on Gem Tester instruments
PostPosted: Wed Jan 29, 2014 12:54 pm 
Offline
Active Member

Joined: Tue Aug 23, 2011 12:51 pm
Posts: 80
I'll do that. Thanks. I did not know that was the technical name for them. Not surprised they are unreliable.

Neil


Top
 Profile  
Reply with quote  
 Post subject: Re: Views on Gem Tester instruments
PostPosted: Thu Jan 30, 2014 7:19 am 
Offline
Valued Contributor
User avatar

Joined: Tue Oct 20, 2009 3:34 pm
Posts: 381
Location: Sweden
NeilS wrote:
I'll do that. Thanks. I did not know that was the technical name for them. Not surprised they are unreliable.

Neil


IMHO they are NOT unreliable, you just have to use them as they are meant to be used - As a part of identification, not as the only instrument to identify a gemstone...

_________________
~~~Lennie~~~


Top
 Profile  
Reply with quote  
 Post subject: Re: Views on Gem Tester instruments
PostPosted: Thu Jan 30, 2014 8:44 am 
Offline
Active Member

Joined: Tue Aug 23, 2011 12:51 pm
Posts: 80
Thanks Lennie. I have been reviewing some threads on the issue, and I picked up that at a minimum, perfect surface luster is indispensable for the instrument to work properly. That would not be any help for the task I was trying to do, which was get an ID on a tiny stone set in jewelry. The polish didn't look very good, and it was hard to access the stone with any kind of instrument. BUT -- with dedicated effort I was able to get my handheld spectrometer in the right spot, and some light behind it. And bingo, there was the signature spectrum for ruby, including a big, bright chromium transmission line. With that, and a good dichroscope reading, I was able to make a good enough call for the project in hand.

Thanks,

Neil


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC - 4 hours


Who is online

Users browsing this forum: Google [Bot] and 10 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock