My grandpa collected rocks and found this somewhere in Nevada. It weighs about 70 pounds.

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closed as off-topic by user12525, uhoh, Peter Jansson, Jan Doggen, arkaia Jul 13 at 15:54

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  • $\begingroup$ Green!?! Is the color of the picture distorted?? $\endgroup$ – JeopardyTempest May 12 '18 at 22:36

It appears to be serpentine which is common in parts of Nevada. Its composed of hydrated magnesium silicates. Its a source of both asbestos and magnesium.

  • $\begingroup$ I don't think serpentine would weather like that. Check and see if you can scratch it with a knife $\endgroup$ – haresfur May 14 '18 at 22:37
  • $\begingroup$ @haresfur yep. Could be some form of silica maybe? A knife test would really help here. $\endgroup$ – Gimelist May 14 '18 at 22:52

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