Tags: Chemical Substance, Mineral.
Coffinite is a uranium-bearing silicate mineral with formula: U(SiO4)1-x(OH)4x.It occurs as black incrustations dark to pale-brown in thin section. It has a grayish black streak. It has a brittle to conchoidal fracture. The hardness of coffinite is between 5 and 6.It was first described in 1954 for an occurrence at the La Sal No.
