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What does GDT stand for in gemmology? https://www.gemologyonline.com/Forum/phpBB2/viewtopic.php?f=27&t=20674 |
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Author: | Gem 14 [ Thu Jan 01, 2015 10:26 pm ] |
Post subject: | What does GDT stand for in gemmology? |
I know this may be elementary for most of you. but its the first time for me! Reading through old exam papers I found a reference to GDT. What does it stand for please? |
Author: | Barbra Voltaire, FGG [ Fri Jan 02, 2015 12:20 am ] |
Post subject: | Re: What does GDT stand for in gemmology? |
Can you please put this in context of how it was used? Thanks. |
Author: | Nathan Renfro [ Fri Jan 02, 2015 12:52 am ] |
Post subject: | Re: What does GDT stand for in gemmology? |
Garnet Topped Doublet |
Author: | Gem 14 [ Fri Jan 02, 2015 7:47 am ] |
Post subject: | Re: What does GDT stand for in gemmology? |
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 |
Author: | Keirkof [ Fri Jan 02, 2015 12:16 pm ] |
Post subject: | Re: What does GDT stand for in gemmology? |
Wikipedia has a nice page on doublets that contains the most important points. |
Author: | Nathan Renfro [ Fri Jan 02, 2015 3:37 pm ] |
Post subject: | Re: What does GDT stand for in gemmology? |
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. |
Author: | roshanravan [ Fri Jan 02, 2015 5:02 pm ] |
Post subject: | Re: What does GDT stand for in gemmology? |
Nathan is right, GTD sometimes used as a trade name for any doublet (Natural, imitation, synthetic) |
Author: | Stephen Challener [ Fri Jan 02, 2015 5:37 pm ] |
Post subject: | Re: What does GDT stand for in gemmology? |
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... |
Author: | Gem 14 [ Fri Jan 02, 2015 9:03 pm ] |
Post subject: | Re: What does GDT stand for in gemmology? |
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. |
Author: | Barbra Voltaire, FGG [ Fri Jan 02, 2015 9:15 pm ] |
Post subject: | Re: What does GDT stand for in gemmology? |
YAG, CZ, SG, RI, LWUV, SWUV, GIA, AGL, CIBJO, NAJA ? 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. |
Author: | Gem 14 [ Fri Jan 02, 2015 9:23 pm ] |
Post subject: | Re: What does GDT stand for in gemmology? |
Barbra Voltaire wrote: YAG, CZ, SG, RI, LWUV, SWUV, GIA, AGL, CIBJO, NAJA ? 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. |
Author: | albertora [ Mon Nov 20, 2017 7:57 am ] |
Post subject: | Re: What does GDT stand for in gemmology? |
GDT Stand for Garnet Topped Doublet... |
Author: | Alan F. [ Tue Nov 21, 2017 12:47 pm ] |
Post subject: | Re: What does GDT stand for in gemmology? |
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. |
Author: | Alan F. [ Tue Nov 21, 2017 12:48 pm ] |
Post subject: | Re: What does GDT stand for in gemmology? |
Sorry, Challener! |
Author: | Debbie K [ Sun Sep 02, 2018 7:31 pm ] |
Post subject: | Re: What does GDT stand for in gemmology? |
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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