It also is deposited from hot underground solutions. Its common habit is as coatings on other minerals. The luster is very high and attractive and some specimens show a nice fluorescent red under ultraviolet light. Color is white, gray or yellow. Luster is adamantine.
Crystals are translucent.
Crystal Habits are small tabular to pyramidal or horn-like crystals usually seen as coatings or crusts on other minerals. Cleavage is distinct in one direction. Fracture is conchoidal. Hardness is 1 - 2. Streak is white.