Stannite is a rare copper, iron, zinc, tin sulfide, with hard to find, well-crystallized specimens generally found only at the Yaogangxian or in Bolivia. Crystals of this size are very rare, almost never seen from either locale The intergrown crystals have a good, metallic luster, and the steel-grey color has just a hint of brassy-yellow that is indicative of the species. This is a quality, textbook Stannite of huge size from the famous Yaogangxian Mine of China. I bought it in China in 2019 but I suspect it is from much older finds, as I have seen no others on the market of this size, but I know some turned up in the early 2000's.