It is found only as crystals, which belong to the trigonal or monoclinic pseudo-hexagonal system and usually have the form of acute double pyramids terminated by the basal planes; the faces of the hexagonal pyramids are striated horizontally, and parallel to the basal plane there is a perfect cleavage. The crystals are white in color and are translucent. The hardness is 4.5 and the specific gravity is 4.36. Light which has traversed a crystal of Durite exhibits a characteristic absorption spectrum.