Polybasite
![](/Images/godic/202502/03/Polybasite_-_Arizpe,_Sonora,_Mexico5002.jpg")
![Unusual polybasite specimen from Mayo Mining District, Yukon Territory, Canada. Size 3.0 x 2.2 x 1.3 cm.](/Images/godic/202502/03/Polybasite-tmu16a5003.jpg")
Polybasite is a sulfosalt mineral of silver, copper, antimony and arsenic. Its chemical formula is [(Ag,Cu)6(Sb,As)2S7][Ag9CuS4].
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.