Polycrase

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

Weighing the right way

Recognize and detect the effects of electrostatic charges on your balance

Daily Sensitivity Test

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

References

• Mindat with location data
• Webmineral