Specimens Calomel is a somewhat rare mineral and is never found in large quantities. It is most often a secondary mineral that forms from the alteration of cinnabar or other mercury minerals. 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.