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Polycrase or polycrase-(Y) is a black or brown metallic complex uranium yttrium oxide mineral with formula: (Y,Ca,Ce,U,Th)(Ti,Nb,Ta)2O6. It crystallizes in the orthorhombic system with typically radial prismatic crystal form. It has a Mohs hardness of 5 to 6 and a specific gravity of 5. It is radioactive due to its uranium content (around 6%). It occurs in granitic pegmatites.

Additional recommended knowledge

It was first described in 1870 at Rasvag, Hidra (Hittero) Island, near Flekkefjord, Norway. It is found in Sweden, Norway, and the United States.


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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Polycrase". A list of authors is available in Wikipedia.
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