Freibergite is a complex sulfide of silver, copper, iron, antimony and arsenic with formula (Ag,Cu,Fe)₁₂(Sb,As)₄S₁₃. It has cubic crystals and is formed in hydrothermal vents. The mineral was discovered in 1853 near Freiberg, Saxony. The term sulfide (sulphide in British) refers to several types of chemical compounds containing sulfur in its lowest oxidation number of -2. ... A hydrothermal vent A hydrothermal vent is a fissure in a planets surface from which geothermally heated water issues. ... 1853 was a common year starting on Saturday (see link for calendar). ... Freiberg, Obermarkt square Freiberg is a city in Saxony, Germany, capital of the district Freiberg. ...