RWA3006
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Member since March 2009
Posts: 4,633 
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Post by RWA3006 on Oct 7, 2020 22:28:39 GMT -5
This is one of my most prized finds. Can you guess what it is? Clues: about 75 pounds. Waxy luster. Rings like a bell when struck with a hammer. Very tough ... so tough that a chip couldn't be hammered off an edge ... only crushed off some fibrous mini shards. Semi translucent... strong flashlight will get through about 4 inches. Found in central Wyoming.  |
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Post by Pat on Oct 7, 2020 22:31:40 GMT -5
Sounds like jade; doesn’t look like jade. Interesting.
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RWA3006
Cave Dweller
Member since March 2009
Posts: 4,633
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Post by RWA3006 on Oct 7, 2020 22:32:01 GMT -5
Another clue... specific gravity tested close to 3.1
If memory serves...
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Post by stephan on Oct 7, 2020 22:54:20 GMT -5
Sounds like a bell? I’ll get a little more specific than Pat: nephrite, though 3.1 is at the upper end of the SG range. Wyoming nephrite, I think, is pretty common with a white rind, but I’ll admit the texture is strange. But “translucent”, “rings like bell” and “tough” are the hints I’m zeroing in on.
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Post by stephan on Oct 7, 2020 23:00:26 GMT -5
And fibrous
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Post by jasoninsd on Oct 7, 2020 23:36:04 GMT -5
Curious if this is only found in WY, or is it possible it could be found across the border in SD? I've done work in WY, but never hounded over there, but this material looks familiar...as if I've seen it recently. Not a piece THAT size mind you!
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dreamrocks
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Post by dreamrocks on Oct 8, 2020 7:36:16 GMT -5
Humm most prize possession?
If not nephrite (mutton fat jade)
Not Dino do do
Not white jade or serpentine
Here’s my long shot of a guess
What about a soft shelled lizard or turtle egg (some of the first Dino’s and lizards, turtles laid eggs that were a soft shelled egg like leather) if so it was buried long ago and why it has such a odd shape for a egg.
If so that would be a rare find and most certainly your most prized possession?
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RWA3006
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Member since March 2009
Posts: 4,633
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Post by RWA3006 on Oct 8, 2020 8:48:48 GMT -5
OK, more clues ...
I found it in a remote area where I found an unexploited jade deposit. On that trip I filled the pickup with nephrite and had found about 80 pounds of it within 50 yards of our mystery rock. The country rock in the area was a mix of granite in various stages of weathering, some poor quality serpentine, and a few knolls of grainy sandstone nearby. Nothing else remotely similar to the mystery rock was anywhere in the area ... except the nephrite. The nephrite was typical dark Wyoming material loaded with iron.
Furthermore, the stone was found near a mountain range where there is nothing similar I could find uphill that glaciers might have transported to the area, at least in the last few dozen millenia. The mountain range is substantial enough to have blocked glaciers from other distances... 13,000 feet. I'm convinced the stone originated along side the nephrite lenses I found.
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Post by stephan on Oct 8, 2020 8:49:23 GMT -5
Humm most prize possession? If not nephrite (mutton fat jade) Not Dino do do Not white jade or serpentine Here’s my long shot of a guess What about a soft shelled lizard or turtle egg (some of the first Dino’s and lizards, turtles laid eggs that were a soft shelled egg like leather) if so it was buried long ago and why it has such a odd shape for a egg. If so that would be a rare find and most certainly your most prized possession? That would be a very high specific gravity for any siliceous rock, which I would expect a preserved egg to be. 2.5-2.65 would be expected (maybe up to 2.9, if jasperized). And it would be hard, but not tough. |
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Post by hummingbirdstones on Oct 8, 2020 8:52:14 GMT -5
I'm watching for answer with interest 'cuz I got nothing.  |
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lookatthat
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Post by lookatthat on Oct 8, 2020 9:32:27 GMT -5
Jade is super tough.
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RWA3006
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Post by RWA3006 on Oct 8, 2020 9:36:31 GMT -5
Another clue ... my pocket knife won't scratch it. That thing is tough like an anvil.
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RWA3006
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Member since March 2009
Posts: 4,633
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Post by RWA3006 on Oct 8, 2020 9:44:51 GMT -5
One of the things about this stone that really got my attention was when I ran my fingers over it the texture was very slick. "Greasy luster" is an excellent description of how the surface feels.
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dreamrocks
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Post by dreamrocks on Oct 8, 2020 9:54:15 GMT -5
It’s starting to sound like some kind of rare mineral that leached out from all the other minerals that solidified separately from all the other high specific gravity minerals in that one spot that were not compatible each other.
Result of that process is some rare earth element and that was the only piece
No idea from there
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RWA3006
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Member since March 2009
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Post by RWA3006 on Oct 9, 2020 11:02:28 GMT -5
Everyone stumped? I agonized over the question for months so I returned to the area many times, got more greenish nephrite, and always kept a keen eye out for what kind of rocks are in the area.
I never found anything similar except for the nephrite. In fact the mystery rock is identical in every way to the neighborhood nephrite except color.
After every test I could think of except destructive chemical analysis, plus considering the context of the area where it was found I finally tentatively concluded the mystery stone is ... nephrite... without the iron content of it's neighbors.
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Post by stephan on Oct 9, 2020 13:50:55 GMT -5
Everyone stumped? I agonized over the question for months so I returned to the area many times, got more greenish nephrite, and always kept a keen eye out for what kind of rocks are in the area. I never found anything similar except for the nephrite. In fact the mystery rock is identical in every way to the neighborhood nephrite except color. After every test I could think of except destructive chemical analysis, plus considering the context of the area where it was found I finally tentatively concluded the mystery stone is ... nephrite... without the iron content of it's neighbors. Aka muttonfat jade. Highly prized by Chinese carvers. As you mentioned, no iron. So that means all magnesium in the Mg,Fe portion of the chemical formula: Ca₂(Mg,Fe)₅Si₈O₂₂ (OH)₂ Well, another drool-stained shirt. What a prize. I've only ever had material with veins of white. A 75 lb piece is quite a find. Any plans for it? The top would make an exceptional suiseki. None of the additional hints you gave dissuaded me from nephrite, but I never expected a solid chunk of muttonfat. I was thinking rind, but I should have realized it was the wrong texture for that. |
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RWA3006
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Member since March 2009
Posts: 4,633
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Post by RWA3006 on Oct 9, 2020 15:52:25 GMT -5
Everyone stumped? I agonized over the question for months so I returned to the area many times, got more greenish nephrite, and always kept a keen eye out for what kind of rocks are in the area. I never found anything similar except for the nephrite. In fact the mystery rock is identical in every way to the neighborhood nephrite except color. After every test I could think of except destructive chemical analysis, plus considering the context of the area where it was found I finally tentatively concluded the mystery stone is ... nephrite... without the iron content of it's neighbors. Aka muttonfat jade. Highly prized by Chinese carvers. As you mentioned, no iron. So that means all magnesium in the Mg,Fe portion of the chemical formula: Ca₂(Mg,Fe)₅Si₈O₂₂ (OH)₂ Well, another drool-stained shirt. What a prize. I've only ever had material with veins of white. A 75 lb piece is quite a find. Any plans for it? The top would make an exceptional suiseki. None of the additional hints you gave dissuaded me from nephrite, but I never expected a solid chunk of muttonfat. I was thinking rind, but I should have realized it was the wrong texture for that. Me too. Interestingly a significant amount of the green/black nephrite I found in the area had minimal rind. I should rummage up some photos. Tried numerous times to talk myself out of the mutton fat conclusion, but haven't been able to come up with a viable alternative. |
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Post by stephan on Oct 9, 2020 17:59:21 GMT -5
Aka muttonfat jade. Highly prized by Chinese carvers. As you mentioned, no iron. So that means all magnesium in the Mg,Fe portion of the chemical formula: Ca₂(Mg,Fe)₅Si₈O₂₂ (OH)₂ Well, another drool-stained shirt. What a prize. I've only ever had material with veins of white. A 75 lb piece is quite a find. Any plans for it? The top would make an exceptional suiseki. None of the additional hints you gave dissuaded me from nephrite, but I never expected a solid chunk of muttonfat. I was thinking rind, but I should have realized it was the wrong texture for that. Me too. Interestingly a significant amount of the green/black nephrite I found in the area had minimal rind. I should rummage up some photos. Tried numerous times to talk myself out of the mutton fat conclusion, but haven't been able to come up with a viable alternative. One of these days I'll have to do some digging (so to speak) to try to figure out what the rind is. It often has a different texture, so it may not be jade, but an adjacent mineral that formed as the rocks move back up through the crust. It doesn't appear to be hydration like you get with obsidian, and I don't believe the iron leaches out.... one day I'll look into that. As for your specimen, I'm not going to try to talk you out of muttonfat. It makes too much sense. |
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RWA3006
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Member since March 2009
Posts: 4,633
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Post by RWA3006 on Oct 9, 2020 18:34:15 GMT -5
I suspect some of the rind on typical Wyoming nephrite is oxidation resulting from oxygen contact with outer surface.
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RWA3006
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Member since March 2009
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Post by RWA3006 on Oct 9, 2020 19:10:40 GMT -5
 Here's some typical nephrite that was found nearby without rind on much of surface.  |
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