herb
spending too much on rocks
Member since November 2011
Posts: 470
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Post by herb on Mar 4, 2016 11:02:52 GMT -5
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Deleted
Deleted Member
Member since January 1970
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Post by Deleted on Mar 4, 2016 11:15:25 GMT -5
Try a scratch test in a small not so obvious area. I'm guessing a knife will not scratch it. I'm going out on a limb by speculating it is malachite based gem silica. The botroidyly stuff screams agate and the color is sexy. Maybe also nickel based chrysoprase. **is botroidyly a word?
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Deleted
Deleted Member
Member since January 1970
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Post by Deleted on Mar 4, 2016 12:41:53 GMT -5
If a knife does scratch it, then it might be smithsonite.
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Post by captbob on Mar 4, 2016 15:15:40 GMT -5
Could be a Smithsonite, but I'm going with a Hemimorphite.
Chrysocolla would be a very distant 3rd guess.
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herb
spending too much on rocks
Member since November 2011
Posts: 470
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Post by herb on Mar 4, 2016 19:15:39 GMT -5
I heard back from my friend. He (and the rock) is currently in Australia, so communications can be a little slow with the 16 or so hour time difference! He says his fingernail won't scratch it, but steel will. He included another photo with a ruler to give an idea of the size. It weighs 2.8 pounds! I guess since steel scratches it, maybe we are leaning towards smithsonite? All the pics I saw on google images of hemimorphite have a varying degree of blueness to them, so I am leaning away from hemimorphite. Shotgunner asked "is botroidyly a word?" If you are Ned Flanders, botroidyly-diddily is a word :-)
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Post by 150FromFundy on Mar 4, 2016 19:53:39 GMT -5
Smithsonite. Check out Wikipedia image. Colour is right. Botryoidal formation is right. Hardness is right. Specific gravity is 4.5 where quartz is only 2.7. Your rock appears heavy for its size which points to a higher specific gravity.
It is often confused with Hemimorphite, but Hemimorphite has a lighter specific gravity at 3.5.
Darryl.
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Deleted
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Post by Deleted on Mar 20, 2016 18:41:37 GMT -5
Your rock appears heavy for its size which points to a higher specific gravity. Hi Darryl. Would you be so kind as to Tell us how you weighed this by looking? OP can you do a specific gravity and prove Darryl right! He knows his stuff, fo sho'.
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Post by 150FromFundy on Mar 20, 2016 19:23:26 GMT -5
shotgunner - The necessary information was provided. The rock weighs 2.8 pounds. The rock is approximately 5" x 5" and maybe 1" thick. In general, I would say that was a "heavy" rock when compared to a similar sized chunk of silica anything. I'm confident that a specific gravity test would have it higher than 2.65, but only a test will say for sure.
Darryl.
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