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 Post subject: Gemology test
PostPosted: Wed Jul 29, 2015 9:32 pm 
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[pdfview]http://www.geo.utexas.edu/courses/347k/Exams/PDF_Exams/final_exam_review_questions.pdf[/pdfview]


Thought everyone might be interested in the "final example review questions" for a geology course at the University of Texas that has to do with gems.


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 Post subject: Re: Gemology test
PostPosted: Wed Sep 23, 2015 10:16 pm 
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Interesting question(s), So the age old question of why pay more. Flame fusion process is most common, I would assume that makes it the most economical to produce. Large pure crystals produced by Czochralski might be more expensive but basically the same. High pressure high temperature? If color is the most important character for any colored stone, which process produces the best color qualities? There must be a dozen or more synthetic processes by now. I imagine cost of the process dictates the cost of the material, 4c's the rest. But what do I know, Im still in the diamond grading course. maybe by next spring after the diamond labs are complete and I can tackle the colored stones curriculum I can tell you! :)

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 Post subject: Re: Gemology test
PostPosted: Thu Sep 24, 2015 8:20 pm 
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I think the most important criteria is producing a synthetic which is hardest to differentiate from the natural counterpart.


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 Post subject: Re: Gemology test
PostPosted: Thu Sep 24, 2015 8:27 pm 
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I think Czochralski pulled material's other big advantage is the large size they can be made in without splitting.

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 Post subject: Re: Gemology test
PostPosted: Thu Sep 24, 2015 8:47 pm 
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So we are still saying size matters all other qualities being equal. That would hold true regardless of synthetic or natural. And maybe that was their point.

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 Post subject: Re: Gemology test
PostPosted: Thu Sep 24, 2015 9:21 pm 
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except it states that it isnt related to size, color, clarity, weight, or any mineralogical differences. So does that put us into a price difference due to geographical location? cultural preferences? Shady dealers with unscrupulous intentions?

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 Post subject: Re: Gemology test
PostPosted: Thu Sep 24, 2015 9:43 pm 
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Dan&Sally wrote:
except it states that it isnt related to size, color, clarity, weight, or any mineralogical differences. So does that put us into a price difference due to geographical location? cultural preferences? Shady dealers with unscrupulous intentions?

Are you still talking about synthetics. or is our train veering off track.


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 Post subject: Re: Gemology test
PostPosted: Sat Sep 26, 2015 7:57 am 
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Yes still pondering the original test question of why you would pay more for synthetic ruby at a wholesaler for different synthetic with all things being equal? I'm stumped.

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 Post subject: Re: Gemology test
PostPosted: Sat Sep 26, 2015 11:58 am 
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Uhm, because one is higher quality than another.
Kinda like a diamond.
Why can we buy one 1.00 carat diamond for $800 and another 1ct diamond for $21,000?


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 Post subject: Re: Gemology test
PostPosted: Sat Sep 26, 2015 4:40 pm 
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what is left out of the list is "cut".

that is, a really nice cut can make a difference in the value of a stone.


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 Post subject: Re: Gemology test
PostPosted: Sat Sep 26, 2015 11:08 pm 
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dchallener wrote:
what is left out of the list is "cut".

that is, a really nice cut can make a difference in the value of a stone.

Yes, again quality, n'est pas?


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 Post subject: Re: Gemology test
PostPosted: Sun Sep 27, 2015 2:10 pm 
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Yes, the overall quality.

But quality is measured by..
Color (which is a physical property)
Carat weight (which is a physical property)
Clarity (which is a physical propery)

and
Cut (which is an aesthetic property) (if I have spelled aesthetic correctly)

I think the first three were mentioned, but not the last.


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