This marcasite is from the Lubin Mine in Lubin, Lubin District, Legnica, Lower Silesia, Poland. It is a copper mine that contain 26 different mineral species including marcasite. It is a sulfide that contains the elements Fe, and S. This specimen is made emtirely of crystalline marcasite and marcasite crystals.The crystals are mostly orhthorhombic some are stacked, some druse and some hoppered. They have a brassy color with colorful iridescent areas and a sub-metallic luster. This piece measures 2 x 2 x 1inches or 50 x 50 x 25 mm.