Marcasite

For a spectacular large display of bright metallic crystallized sulphides, this 19 x 16 cm wide plate from the famous Picher Field area in the Tri-State District, Oklahoma is really great. The thin, siliceous, cherty cream-coloured host rock is liberally covered in over a hundred blue-grey metallic cubes of Galena, most of which show naturally truncated corners as they have started to develop in a cubo-octahedral form. Many of these crystals form small groups of two or three crystals, but all maintain excellent crystal form with those across the centre of the plate partially encrusted with bright golden to brassy pointed Marcasite crystals. The largest Galena crystal reaches 1.7 cm on edge but most are around 1 cm across and there is very little damage to be seen. Underneath, and in between the Galena crystals the matrix is dotted with small, glossy, orange-brown Sphalerite crystals and more small Sphalerite crystals coat the back of the specimen.
Ex Hettrich Collection.