New Mineral Named After GIA’s John Koivula
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 Post subject: Quick Summer Quiz
PostPosted: Thu Jul 03, 2008 12:06 pm 
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Hi all,

Was taking some photos for the site and starting playing around with a few things. Came up with this shot and thought it may make a decent little quiz.

Image

The stones here are all of the same species. It is a doubly refractive species, harder than apatite and softer than sapphire. It is not tourmaline and the stones in the photo are from very different localities.

Any guesses so far? Extra credit for naming the varieties!

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PostPosted: Thu Jul 03, 2008 12:21 pm 
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I'll have a guess:

kunzite, spodumene, hiddenite


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PostPosted: Thu Jul 03, 2008 12:47 pm 
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Good guess, but you'll have to try again! :wink:

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PostPosted: Thu Jul 03, 2008 3:33 pm 
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Beryls? Morganite, aquamarine, heliodor?

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PostPosted: Thu Jul 03, 2008 4:48 pm 
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Is it topaz?


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PostPosted: Thu Jul 03, 2008 7:34 pm 
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Zircon!

pink tanzania
Green Burma/Sri Lanka
Blue cambodia/vietnam

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PostPosted: Fri Jul 04, 2008 2:54 pm 
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Perhaps more challenging than I suspected! :twisted:

Ok, let's see. Softer than any of the guesses so far - though we are not talking about some obscure rarity that is a 3 or something like that, I promise. Higher RI than Beryl.

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PostPosted: Fri Jul 04, 2008 3:19 pm 
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The blue one is throwing me off. I can come up with species that come in blue and pink or blue and green or pink and green but not blue pink and green. Hmmmmmmmmmm. Have any of these stones been treated?

J-

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 Post subject: Gem Quiz
PostPosted: Fri Jul 04, 2008 3:55 pm 
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Ok, lets do this by elimination; using mineralogy text

original parameters

harder than apatite (5); softer than beryl (8); double refraction

then "softer than any of the guesses so far" zircon (7)

hardness range >5 x <7

Blue Minerals
Lazurite
Riebeckite
Turquoise
Lazulite
Sodalite
Lawsonite
Plagioclase (Feldspar)
Glaucophane
Benitoite
Kyanite
Vesuvianite

Pink to Violet
Tremolite
Scapolite
Rhodonite
Opal
Inesite
Tephroite
Zoisite
Jadeite
Spodumene (already guessed, so should be softer <6 1/2)
Garnet

Green
Titanite
Analcime
Datolite
Actinolite
Hedenbergite
Hornblende
Pargasite
Hypersthene
Augite
Diopside
Scapolite
Tourquoise
Willemite
Opal
Orthoclase
Pumpellyte
Acmite
Prehnite
Zoisite
Kyanite
Epidote
Vesuvianite
Jadeite
Spodumene
Olivine
Garnet

No matches with pink/violet except spodumene which has already been eliminated. Matches with blue and green:

Turquoise (definitely not this)
Kyanite
Vesuvianite
Feldspar (Plagioclase and Orthoclase)

I give up.

John

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PostPosted: Fri Jul 04, 2008 9:42 pm 
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Jason, none have been treated. In fact, I have never heard of any treatment done to this species.

John, all I can say is that there seems to be an omission in the pink/violet list from the text you've used.

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PostPosted: Sat Jul 05, 2008 4:44 pm 
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Hi Brad,

I guess they are all feldspars, of one variety or another (Though if recent debate is anything to go by then at least some of these may be treated...so maybe not) :roll:

I don't think I'm being very decisive here. :)

Frank


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PostPosted: Sun Jul 06, 2008 1:13 am 
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Scapolite can occur in those colors.


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PostPosted: Sun Jul 06, 2008 5:12 am 
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So far, the you gave mentions:

- doubly refractive
- hardness between apatite and zircon
- RI above beryl (how hard is that!)
- those colors

clearly, the academic ID method would be to work through that list of probabilistic possibilities, but that sounds more like writing a boring book then answering a little Sunday quiz. And ya' never know... :roll:

Chrysoberyl I'd say.

Right :?:


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PostPosted: Sun Jul 06, 2008 9:33 am 
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Then it must be Vesuvianite , though the blue doesn't seem to fit as per any info I can find.

Zoisite is another strong possibility except that you say it's not a treated material and tanzanite is usually treated.

If it's Vesuvianite , I can't find any mention of color based names, such as with Kunzite, so that spec isn't met.

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PostPosted: Sun Jul 06, 2008 12:00 pm 
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I think we need more clues.
Just goes to show you, they could be several things, all impossible to identify without proper test results.


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