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 Post subject: Blues Quiz
PostPosted: Tue Jan 02, 2007 4:45 pm 
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All the stones above have similar colors. All the stones above are different gem minerals. Name that stone!

Using standard gemological tools:
1. Polariscope: singly refractive
Refractive Index: 1.434
Specific gravity: 3.18
Pleochroism: none
Extra: With magnification, I can see a splintery fracture

2. Polariscope: doubly refractive
Refractive Index: 1.624-1.644:
Specific gravity: 3.06
Pleochroism: 2 colors
Extra: UV inert

3. Polariscope: doubly refractive
Refractive Index: 1.716-1.731
Specific gravity: 3.68
Pleochroism: moderate
Extra: Color Zoning, fibrous appearance

4. Polariscope: doubly refractive
Refractive Index: 1.577-1.583
Specific gravity: 2.72
Pleochroism: Weak, 2 colors
Extra: liquid filled tubes visible with microscope

5. Polariscope: doubly refractive
Refractive Index: 1.762-1.770
Specific gravity: 4.00
Pleochroism: 2 colors visible
Extra: With magnification, needles intersecting at 60 degrees

6. Polariscope: singly refractive
Refractive Index: 1.718
Specific gravity: 3.60
Pleochroism: none
Extra: microscopic octahedral inclusions

7. Polariscope: doubly refractive
Refractive Index: 1.619-1.627
Specific gravity: 3.53
Pleochroism: none
Extra: With magnification, I can see a splintery fracture

8. Polariscope: singly refractive
Refractive Index: 1.498
Specific gravity: 2.45
Pleochroism: none
Extra: greasy luster

9. Polariscope: doubly refractive
Refractive Index: 1.691-1.700
Specific gravity: 3.35
Pleochroism: strong blue and purple
Extra: With magnification, I can see a evidence of cleavage in a fracture

10. Polariscope: doubly refractive
Refractive Index:1.757-1.804
Specific gravity: 3.68
Pleochroism: Strong, colorless and blue
Extra: high dispersion


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 Post subject:
PostPosted: Tue Jan 02, 2007 5:45 pm 
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Nailed it in less than 10 minutes with GT Pro. :) Everyone needs a copy!!!

I think that 8 is a dead giveaway based on visual ID only. Anyone else agree? ;)


Last edited by gem-n00b on Wed Jan 03, 2007 12:40 pm, edited 1 time in total.

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PostPosted: Tue Jan 02, 2007 5:52 pm 
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Well, I'm a rookie and don't have any reference except an old mineralogy text, but I'll try a few.
1 Flourite
2 Lazulite
3 ?
4 Aqua
5 sapphire
6 spinel
7 ?
8 ?
9 Tanzanite
10 iolite

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Handmade Enterprises LLC


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 Post subject:
PostPosted: Tue Jan 02, 2007 8:57 pm 
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I'll bet #8 has everyone stumped. The others are textbook. 10 minutes without a software program (although it would be nice to have). :)


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PostPosted: Tue Jan 02, 2007 9:14 pm 
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For #8 I am guessing Hauyne (for one reason its so small).

Is number #3 Kyanite?

Just about the rest I can figure out.


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PostPosted: Tue Jan 02, 2007 10:30 pm 
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Ok, I think 7 out of 10 have been identified correctly, taking into account ALL answers.
Someone give me a complete list. :P


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PostPosted: Tue Jan 02, 2007 10:45 pm 
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Any chance #8 is just glass?


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PostPosted: Tue Jan 02, 2007 10:49 pm 
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MoDo wrote:
Any chance #8 is just glass?


The RI and SG could be glass but the luster of glass would be vitreous and this is a little greasy.

Actually 8 has been ID'd correctly. It is Hauyne from Germany.


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PostPosted: Tue Jan 02, 2007 10:49 pm 
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Morning Dove wrote:
Any chance #8 is just glass?


Greasy luster, MoDo.

Rick Martin


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PostPosted: Tue Jan 02, 2007 10:53 pm 
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Location: The frozen north prairie :-/
:oops:


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PostPosted: Tue Jan 02, 2007 11:00 pm 
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1. Fluorite
2. Indicolite (Blue Tourmaline)
3. Kyanite
4. Aquamarine
5. Corundum/Sapphire
6. Spinel
7. Blue Topaz
8. Hauyne
9. Tanzanite/Zoisite
10. Benitoite


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PostPosted: Tue Jan 02, 2007 11:02 pm 
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I don't know if I got them all right, but that last one was tricky. I am pretty sure its Benitoite. The hint about the pleochroism was helpful.


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PostPosted: Wed Jan 03, 2007 1:13 am 
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WE have a winner!!!
Ben got all of them correct.
I think you mis typed...the dispersion clue was helpful with the benitoite right?
Well done!


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PostPosted: Wed Jan 03, 2007 4:33 am 
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I was joking about number 8 being obvious. :) Hauyne is one of those stones that you just don't see that often. I probably wouldn't have got it without the software to help.


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PostPosted: Wed Jan 03, 2007 10:43 am 
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Oh awesome! Never had a chance to do a quiz before and was glad to be try this time. So do I win all the gemstones in the photos? ;-)


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