Dora
spending too much on rocks
Member since September 2012
Posts: 252
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Post by Dora on Nov 24, 2012 5:58:12 GMT -5
I was pre-shaping some California calcite to tumble and it started to become harder and to show a darker color on the inside. As I continued a tiny green crystal jumped out of it, as I inspected the stone I observed a small section with green inclusions. I’m trying to figure out what are the green crystals and the darker material inside. I was thinking the green material could be epidote, but I’m not sure. Perhaps the dark material inside could be feldspar with quartz, but I’m not sure either. I’m hoping someone has found something like this before and could give me a better idea of what it is. pics:
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Post by NatureNut on Nov 24, 2012 7:13:16 GMT -5
Actinolite maybe?
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Sabre52
Cave Dweller
Me and my gal, Rosie
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Post by Sabre52 on Nov 24, 2012 18:08:18 GMT -5
Wow that is bright green, maybe uvaroite ( chromium) garnet. It would be pretty hard....Mel
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Dora
spending too much on rocks
Member since September 2012
Posts: 252
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Post by Dora on Nov 24, 2012 23:03:11 GMT -5
Thanks for helping! Checked both (actinolite & uvarovite) on Google and the crystals really look like the tiny uvarovites. Either that or something very similar. If that's the case then the matrix might contain some chromite, it’s really hard. I'll be more careful with the rest of the material and will strip off all the calcite on one, to inspect the matrix better.
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Deleted
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Post by Deleted on Nov 30, 2012 14:48:44 GMT -5
actinolite is definitely not in the equation. Color of actinolite is more of a sage green. This certainly looks chrome-y. Nice find.
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Post by mohs on Nov 30, 2012 23:40:05 GMT -5
i was just reading a mineral book if its crystallized it probably leans towards epidote and you said the it got harder as you tumbled it but if it scaly or flaky then it would lean more towards chlorite group
Ed
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Post by mohs on Nov 30, 2012 23:43:27 GMT -5
o and apatite is another possibility mohs hardness of 5
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Dora
spending too much on rocks
Member since September 2012
Posts: 252
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Post by Dora on Dec 1, 2012 8:16:20 GMT -5
Thanks to both of you for the helpful information Ed, so far I'm torn between epidote and uvarovite. When I look at both on Google images the little crystals looks like uvarovite, but still could be epidote as both of them could be found in calcite and are also found in California. And yes, the darker grey material is hard and also shines. Its hardness on the Mohs scale fall between 6 and 7, perhaps feldspar. Identifying them is not easy because the crystals are tiny and I discovered them right after I went over them with my dremel. I placed one of the calcite specimens in vinegar/ammonia to try to get rid of some of the calcite and see what I can find, but that will take some time.
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Post by mohs on Dec 1, 2012 10:21:46 GMT -5
I've never tried the calcite in vinegar trick I suppose it is a slow fizzle...mostly
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Dora
spending too much on rocks
Member since September 2012
Posts: 252
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Post by Dora on Dec 1, 2012 19:01:27 GMT -5
;D I haven't done that before either! I found the instructions here: www.ehow.com/how_8529764_remove-calcite-crystals.htmlThe vinegar acts very slowly but the ammonia is faster, still it will take some time because of its size. Here is it on ammonia, as it dissolves it starts to settle on the bottom. In the photo you can see the dissolved accumulation in the lower part of the plastic container. Let’s see if I find something interesting.
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Post by mohs on Dec 1, 2012 21:29:07 GMT -5
that is really interesting and informative I had no real idea that --they did that to get to the crystal hopefully you'll end up with the Philosophers Stone which was emerald in many traditions good luck with your experiment
Ed
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Dora
spending too much on rocks
Member since September 2012
Posts: 252
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Post by Dora on Dec 2, 2012 4:26:20 GMT -5
Thanks Ed! ;D
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metalsmith
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Post by metalsmith on Dec 23, 2012 14:39:08 GMT -5
something deep in the back of my mind reminds me that epidote and calcite don't co-exist. No, I am not 100% on this...
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Minnesota Daniel
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Post by Minnesota Daniel on Dec 31, 2012 0:13:43 GMT -5
Chrome diopside occurs in calcite and marble. It's about the right color.
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