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Post by eriktheawful on Sept 18, 2008 4:52:43 GMT -5
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Post by eriktheawful on Sept 18, 2008 4:57:46 GMT -5
I found this in some granite boulders with lots of massive biotite. It is a translucent peach color and has a strong schiller effect when the light hits it at a corner. It has perfect rhombehedral clevage and a hardness of 4. It doesn't bubble in cool acids (weak HCL or acetic). It has a white streak. This piece is crysalized but I have another that is massive material. Both are on biotite with fine grained quartz behind the mica. I was thinking one of the major three C03 minerals, but it obviously isn't calcite.
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Post by gemlover on Sept 18, 2008 19:10:29 GMT -5
Dolomite? Like limestone/marble but won't react to acid.
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Post by amythestguy on Sept 18, 2008 20:03:03 GMT -5
Is that from the braselton place?
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Post by arappaho on Sept 18, 2008 21:00:10 GMT -5
Everything looks and sounds like calcite.
I'm just wondering why it obviously isn't???
The schiller sounds like feldspar, but the hardness and cleavage don't.
Interesting find.
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Post by nose2ground on Sept 18, 2008 21:54:56 GMT -5
that's not from the Hwy. 60 area is it?
I would wonder if the "peachy" color came from all the iron we apparently have around here. Odd though, I have seen this before - ??
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Post by eriktheawful on Sept 19, 2008 7:02:59 GMT -5
Can't be calcite b/c calcite will bubble readily in a weak (10:1) HCL acid solutrion even when cool. Now the the other basic carbonates won't they will bubble some in a stronger warm or hot solution. The perfect clevage and hardness really screams calcite I agree. Also not florescent under LW uv.
Amguy- This is found at the braselton site. Not much of it there but it is there.
I think I may have my geology prof. look at it and see what he thinks. Maybe I can run down a better test of it after class on saturday using the lab. May have to try blowpiping it.
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Post by lynskyn1970 on Sept 20, 2008 17:22:28 GMT -5
pretty whatever it is!!!!
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Post by eriktheawful on Sept 23, 2008 5:44:57 GMT -5
Dolomite is the answer it would seem after more testing.
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Post by arappaho on Sept 23, 2008 21:23:32 GMT -5
Kudos for this post,Erik.  It has been very helpful to me. I was thinking the only other thing it could be was Hemimorphite, but everything didn't fit right for that either. And I wouldn't recognize a piece of Hemimorphite if it bit me in the nose. And I was saying to someone just recently that I needed to read up on Dolomite. The only Dolomite I could recognize was Marble. So this really got the ball rolling.  Was it further cleavage testing that turned you toward Dolomite? Thanks, Joe |
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Post by colorshapetexture on Sept 23, 2008 21:28:46 GMT -5
Looks like feldspar. The sheen with the cleveage.
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Post by arappaho on Sept 24, 2008 20:49:03 GMT -5
That's what I thought at first, too, Jim. And the biotite.......?
Erik, I guess you are just going to have to powder some up and see if it fizzez.
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Post by gemlover on Sept 25, 2008 1:35:54 GMT -5
if calcite, not dolomite, should fizz without grinding it up. feldspar will not fizz, but is much harder than most carbonates.
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Post by eriktheawful on Sept 25, 2008 6:04:47 GMT -5
nope. dolomite does in fact dissolve slowly if ground up and in warm acid. This did. Appears the schiller effect and color is from some iron impurities/
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