Minerals in space group 137

Coccinite is a rare mercury iodide mineral with chemical formula of HgI2, mercury(II) iodide. It was first discovered in Casas Viejas, Mexico; it has also been reported from Broken Hill, New South Wales, and from a uranium mine in Thuringia and old mercury workings in the Rhineland-Palatinate in Germany. At the Thuringia deposit the mineral occurs as a sublimation product resulting from fires associated with pyrite-bearing graptolitic slate.