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. Fluorescent red and crystals darken upon exposure to light over time. Associated Minerals include mercury , cinnabar , metacinnabar and other mercury minerals. Best Field Indicators are density, associations, fluorescence, hardness and crystal habit.