Specimens Zinkenite is one of a few sulfide minerals that form fine acicular crystals that appear as hair-like fibers. The fibrous aggregates may be so thick as to cover a specimen with a mat of hair-like fibers or it may be sparsely dessiminated between other minerals and may be confused with stray hairs or dark lint. Jamesonite , boulangerite and millerite are other sulfides that form similar acicular crystals. Zinkenite is a sulfosalt, a segment of sulfides where the antimony acts more like a metal than a non-metal and occupies a position where it is bonded to sulfurs. A variety of zinkenite from Tasmania contains a small amount of silver.
Color is steel gray to gray.
Luster is metallic. Crystals are opaque. Crystal Habits include dense or sparse felted masses of acicular crystals. Larger crystals show hexagonal prismatic and pyramidal forms. Streak is steel gray.