Rare as radiating groups of black bladed crystals less than 0.5 mm with variscite, fluellite, cacoxenite, hewettite, and leafy green nevadaite. More abundant as sooty black patches up to 10 cm across on jasperoid rock, which consist of druses of spherical clusters resembling black velvet. Fervanite, schubnelite, hewettite, and tyuyamunite are common associates. [Mineralogical Record: 26(5): 449-469]
Habit:
Radiating groups of bladed crystals to less than 0.5 mm. Sooty patches resembling velvet [Mineralogical Record: 26(5): 449-469]
Gold Quarry Mine, Maggie Creek Mining Subdistrict, Carlin Trend, Eureka County, Nevada, USA