257 Fluorite with Pyrite and Sphalerite from UK – 57g & 45x66x22mm – Fluorite is a mineral consisting of calcium fluoride. It typically occurs as cubic crystals, colourless when pure but can be coloured by impurities. Pyrite, or Iron Pyrite, also known as Fool’s Gold, is an iron sulphide. The metallic lustre and pale brass-yellow hue give it a resemblance to gold. Sphalerite is a shiny mineral, yellow to dark brown or black in colour, consisting of zinc sulphide.