Abstract
Minerals containing iodine as an essential constituent are of rare occurrence in nature. The most common, and that first described, is silver iodide, which was analysed by Vauquelin in 1825; hexagonal crystals of iodyrite were described by Des Cloizeaux in 1854. Other iodides are marshite and the new mineral miersite ; iodobromite and schwartzembergite also contain considerable amounts of iodine. The existence of mercury iodide seems to be doubtful; the supposed mercury iodide from Broken Hill consists of an intimate mixture of cinnabar and iodyrite. Two iodates are also known, namely lautarite and dietzeite.