Post subject: Re: What does GDT stand for in gemmology?
Posted: Fri Jan 02, 2015 7:47 am
Established Member
Joined: Fri Mar 21, 2014 9:10 pm Posts: 30
Barbra Voltaire wrote:
Can you please put this in context of how it was used? Thanks.
It's a badly posed exam question and I managed to transpose two letters.
Q : What is GTD? Give 4 observations that would help you identify a GTD? Why were they made?
I'm not sure its fair to use abbreviations in exams. This is the first time I have seen garnet topped doublets referred to in this way but I guess its in common usage.
Were they made initially to reduce costs? It seems like a lot of work unless there is financial gain. Were garnets rarer and more expensive in the past?
Post subject: Re: What does GDT stand for in gemmology?
Posted: Fri Jan 02, 2015 3:37 pm
Valued Contributor
Joined: Tue Apr 30, 2013 1:41 pm Posts: 172
Gem 14 wrote:
Barbra Voltaire wrote:
Can you please put this in context of how it was used? Thanks.
It's a badly posed exam question and I managed to transpose two letters.
Q : What is GTD? Give 4 observations that would help you identify a GTD? Why were they made?
I'm not sure its fair to use abbreviations in exams. This is the first time I have seen garnet topped doublets referred to in this way but I guess its in common usage.
Were they made initially to reduce costs? It seems like a lot of work unless there is financial gain. Were garnets rarer and more expensive in the past?
Thanks Barbara and Nathan
GTD is a silly synonym for a garnet and glass doublet. Im not a particular fan of "GTD" as it isnt terribly informative since the glass component is not described. They were made purely to act as a cheap simulant for expensive stones, namely Ruby, Emerald and Sapphire, while still providing some increased measure of abrasion resistance compared to glass alone.
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How long has it been since garnet-topped doublets were even made? They're practically a historical footnote at this point--I can't imagine anyone this century talking about them so much that they needed an acronym. But maybe things are different in other sides of the trade...
Post subject: Re: What does GDT stand for in gemmology?
Posted: Fri Jan 02, 2015 9:03 pm
Established Member
Joined: Fri Mar 21, 2014 9:10 pm Posts: 30
Scarodactyl wrote:
I can't imagine anyone this century talking about them so much that they needed an acronym.
I agree with you - I think we are heading towards language disaster with everyone over using acronyms! I never use them in exams and find them irritating in any context.
I went on a search for examples of doublets mainly at jewellery auctions and had no luck. I eventually got a nice example from a kind member on this forum for my collection.
I think there are several acronyms which are professionally appropriate....GTD threw me off, even though I see them with some frequency, I always call them garnet and glass doublets.
I think there are several acronyms which are professionally appropriate....GTD threw me off, even though I see them with some frequency, I always call them garnet and glass doublets.
I sometimes wonder if some examiners are purposely trying to trip students instead of testing depth of knowledge in gemmology.
Post subject: Re: What does GDT stand for in gemmology?
Posted: Tue Nov 21, 2017 12:47 pm
Gemology Online Veteran
Joined: Thu Mar 19, 2015 9:55 am Posts: 543
I'm with Stephen Challenor on this one, it must be 50 years since I saw a doublet of any description, and even then it had been picked out of some old jewellery.
Post subject: Re: What does GDT stand for in gemmology?
Posted: Sun Sep 02, 2018 7:31 pm
Active Member
Joined: Thu Jun 14, 2012 7:58 pm Posts: 75
I just saw this post as I rejoined only a few weeks ago, sorry for being so late to the party. But... I just saw two garnet topped doublets last week. They were mixed in with an older gentleman's jewelry store excess/bad stock. I was thrilled to find them! I try to collect as many fake/simulants/synthetics/treated and real, untreated stones as I can of all different types to really be able to see the difference when I test stones. These are red garnet on top with green glass below.
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