Fool's Gold
The chemical composition of pyrite is FeS2, and the crystal is a sulfide mineral of the equiaxed crystal system. The composition usually contains cobalt, nickel and selenium, and has a NaCl-type crystal structure. There are often complete crystal forms, including cubes, octahedrons, pentagonal dodecahedrons and polygonal shapes. There are stripes parallel to the crystal edges on the cubic crystal face, and the stripes on each crystal face are perpendicular to each other. The aggregates are in the form of dense blocks, granules or nodules. Light yellow (copper yellow) color, green-black streaks, strong metallic luster, opaque, no cleavage, jagged fracture. Mohs hardness is relatively high, reaching 6-6.5, and a knife cannot carve it. The proportion is 4.9-5.2. It is easily weathered into limonite under surface conditions.