9 Photos
Polybasite
Chemical Formula	[(Ag,Cu)6(Sb,As)2S7][Ag9CuS4]
Species	Sulfides
Crystal System	Monoclinic
Mohs Scale	2-3
Specific Gravity	6-6.2
Color	Black with dark ruby red internal reflections
Streak	black with reddish tint
Luster	Metallic
Diaphaneity	Opaque
Cleavage	Imperfect/FairImperfect on
Fracture	Conchoidal
Crystal Habit：Always in pseudo hexagonal trillings, as tablets and rosettes
Geological Setting：In low to medium temperature hydrothermal veins

It forms black monoclinic crystals (thin, tabular, with six corners) which can show dark red internal reflections. It has a Mohs hardness of 2.5 to 3. It is found worldwide and is an ore of silver. The name comes from the number of base metals in the mineral.