I found this in a stream in Medicine Bow-Routt National Forest, Wyoming. One side (2/3 length) has a pointy pyramid with four faces; other side (1/3 length) has four faces but with with an edge instead of a point. Color ranges from dark chocolate brown to black with a lacquer-like finish. It interacts very weakly with a rare earth magnet. enter image description here


closed as off-topic by trond hansen, JulPal, Peter Jansson, Semidiurnal Simon, Gimelist Jan 25 at 23:44

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  • $\begingroup$ Thanks Gary. Looks like I better get rid of it as it could be radioactive. $\endgroup$ – user1050483 Jan 25 at 1:08

Your specimen might be a monazite crystal. The color, weakly magnetic and general crystal form would match monazite. The crystal system for monazite is monoclinic which offers a possible explanation for the specimen's asymmetric appearance.

There are plenty of granitic rock in the Medicine Bow-Routt National Forest area


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