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Post by mohs on Sept 1, 2014 11:22:07 GMT -5
I know this is going to be quick I.D. But what are these black rocks? They are at least 7 mohs hard, opaque, dense> These samples are exhibit a natural tumble and pretty polished smooth That gives you some idea of how durable they are. I didn’t find them. So I don’t what area they are from. But they are really cool dense black rocks. Totally the opposite of obsidian Thanks Ed
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Post by mohs on Sept 1, 2014 11:39:44 GMT -5
its such a lousy picture geez!
but I think my description should suffice for an i.d. I'm pretty sure its a common lapidary stone mostly
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Post by Pat on Sept 1, 2014 13:17:09 GMT -5
Ed, could that be jade?
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Post by mohs on Sept 1, 2014 13:23:08 GMT -5
Interesting Pat ! That never crossed my mind hhhmmmmm....
I'll see if I can get a better picture but I suppose its the type of rock that without a visual inspection and a s.g. test it will be hard to tell definitely
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Tommy
Administrator
Member since January 2013
Posts: 12,594
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Post by Tommy on Sept 1, 2014 13:52:49 GMT -5
I can absolutely positively identify those as black rocks. heehee sorry I couldn't resist mostly.
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Post by mohs on Sept 1, 2014 14:02:09 GMT -5
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Post by mohs on Sept 1, 2014 14:15:45 GMT -5
the more research I do I think your right Pat Most likely nephrite found in the U.S. Thanks I would have never made the connection
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Deleted
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Member since January 1970
Posts: 0
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Post by Deleted on Sept 1, 2014 16:56:37 GMT -5
Greetings [edmost] Ed two guesses 1st Basalt an agate bearing Igneous rock & 2nd Chalcedony. Please check out my Sticky's below. -- Please click images to open larger images in a new Tab, same with everything that is Underlined! I currently have a 3lb Beach (UK), Lortone QT 12/66 (USA) rotaries & 2x Viking Vibrasonic (Diamond Pacific) (USA) virbrating tumblers, with Silicon Carbide grit F80, F220, F600, F1200, with Tin Oxide (1.0 micron) & Aluminum Oxide (1.0 micron & 0.3 micron) polishes. I hail from (The Barony of Seabegs) Bonnybridge, Stirlingshire, U.K, where aliens (15mb) sometimes come for a visit & about 4 miles west from that monstrosity & 7 miles west of this new monstrosity! Sticky's: their contents are resource information 1#: Vendors worldwide (2mb), 2#: How to use the forum, 3#: How to identify rocks & minerals, 4#: Save money on expensive grits & polishes, 5#: Aussie Lapidary Forum: Rock Tumbling Guide!
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Post by mohs on Sept 1, 2014 18:58:54 GMT -5
Hey Andrew Howdy !
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Post by kk on Sept 1, 2014 20:21:23 GMT -5
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Post by snowmom on Sept 1, 2014 21:17:56 GMT -5
they look very much like the black rocks I find here, feeling waxy and thick on the outside but cutting hard and smooth inside, very resilient against a hammer, bout can't hurt it with a hammer at all , around 7 mohs hardness... when you break it does it break in a line or conchoidal? To confuse the issue, I have some of each. The nephrite-ish stuff seems to be mildly conchoidal, the solid black seems to break straight. It is much much harder than glass.. jade likely. Other possibilities can be onyx or Chalcedony, here we also have basanite, a heavily silicated basalt morph. lots of times the latter has feldspar inclusions.
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Deleted
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Member since January 1970
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Post by Deleted on Sept 1, 2014 22:53:04 GMT -5
My list would be nephrite, epidot (more translucent), actinolite or hornblend. That is a short list because it only includes some heavier stones (2.9 and up). They do look a lot like some of the stones that snowmom sent to me. Problem is we have not figured out what they are either. Jim
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Post by mohs on Sept 2, 2014 0:29:16 GMT -5
thanks all ! really appreciate it The toughness reminds me of nephrite Although that basanite suggestion rocks maybe I'll slice one open tomorrow that might give more indication the other thing is I’m assuming the 3 rocks are the same material they may not be here's another picture hopefully better
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Post by mohs on Sept 2, 2014 0:35:24 GMT -5
my first impression would be that this material wouldn't break conchroidal they are so natural smooth and seem like a denseness that belies micro crystallization
well that doesn't make sense every thing is crystalized at the microscopic level but not finely packed dense crystallization say like flint
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Post by snowmom on Sept 2, 2014 18:45:51 GMT -5
they sure look the same to me! Have you tried cutting any of it? watching this thread with interest.
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Post by washingtonrocks on Sept 5, 2014 12:20:46 GMT -5
Are ya confident about the mohs 7 result, @mr.mohs? If you are, that would pretty much put it out of the running for Nephrite...although there are exceptions, of course, most Nephrite will be closer to 5.5-6...Maybe 6.5...SG and fracture can tell you a lot. You probably already know Jade almost never exhibits conchoidal fracture...Can you bring yourself to putting the business end of a hammer to one of those black beauties? Having said all of that, they look almost identical to the black Nephrite I find around here.
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