Often the crystals are platy with a hexagonal outline and the hemimorphic character is then not easily distinguished. Color is honey yellow, orange, red or light to dark brown. Luster is adamantine to resinous. Transparency crystals are transparent to translucent. Also seen as crusts or dustings over crystals of calcite , smithsonite and sphalerite .
Fracture is conchoidal.
Streak is red, orange or light brown. Striations on pyramidal faces parallel to base, an index of refraction of 2.50 - 2.52 and is soluble in hydrochloric acid giving off hydrogen sulfide gas Associated Minerals include fluorite , chalcopyrite , quartz , smithsonite , calcite , pyrite , sphalerite , marcasite and prehnite . Best Field Indicators are crystal habit, color, streak and cleavage.