Freibergite is a complex sulfosalt mineral of silver, copper, iron, antimony and arsenic with formula (Ag,Cu,Fe)12(Sb,As)4S13.

It forms one solid solution series with tetrahedrite and another with argentotennantite.

Freibergite is an opaque, metallic steel grey to black and leaves a reddish-black streak.

It is typically massive to granular in habit with no cleavage and an irregular fracture.

The mineral was first described in 1853 from an occurrence in the silver mines of the type locality at Freiberg, Saxony.