The sulfarsenide minerals are a subgroup of the sulfide mineral

Sulfide mineral

The sulfide minerals are a class of minerals containing sulfide as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenides, the tellurides, the arsenides, the antimonides, the bismuthinides, the sulfarsenides and the sulfosalts...

s which include arsenic

Arsenic

Arsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...

 replacing sulfur as an anion in the formula. Antimony

Antimony

Antimony is a toxic chemical element with the symbol Sb and an atomic number of 51. A lustrous grey metalloid, it is found in nature mainly as the sulfide mineral stibnite...

 and bismuth

Bismuth

Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent poor metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead...

 may occur with or in place of the arsenic as in ullmannite

Ullmannite

Ullmannite is a nickel antimony sulfide mineral with formula: NiSbS. Considerable substitution occurs with cobalt and iron in the nickel site along with bismuth and arsenic in the antimony site...

. The chemical formula of a sulfarsenide looks like a sulfosalt, however the structures are distinctly different. In sulfosalts the arsenic replaces a metal ion.

The sulfarsenides are grouped with the sulfides

Sulfide mineral

The sulfide minerals are a class of minerals containing sulfide as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenides, the tellurides, the arsenides, the antimonides, the bismuthinides, the sulfarsenides and the sulfosalts...

 in both the Dana and Strunz

Strunz classification

Nickel–Strunz classification is a scheme for categorizing minerals based upon their chemical composition, introduced by German mineralogist Karl Hugo Strunz in his 1941 Mineralogische Tabellen. The 4th edition was edited by Christel Tennyson too . It was followed by A.S...

 mineral classification systems.

Examples include:

• Arsenopyrite group:
  • Arsenopyrite
    Arsenopyrite
    Arsenopyrite is an iron arsenic sulfide . It is a hard metallic, opaque, steel grey to silver white mineral with a relatively high specific gravity of 6.1. When dissolved in nitric acid, it releases elemental sulfur. When arsenopyrite is heated, it becomes magnetic and gives off toxic fumes...
    
     FeAsS
  • Glaucodot
    Glaucodot
    Glaucodot is a cobalt iron arsenic sulfide mineral with formula: AsS. The cobalt:iron ratio is typically 3:1 with minor nickel substituting. It forms a series with arsenopyrite . It is an opaque grey to tin-white typically found as massive forms without external crystal form. It crystallizes in the...
    
     (Co,Fe)AsS
  • Gudmundite FeSbS
  • Lautite CuAsS
  • Alloclasite
    Alloclasite
    Alloclasite is a sulfosalt mineral. It is a member of the arsenopyrite group. Alloclasite crystallizes in the monoclinic system and typically forms as columnar to radiating acicular prismatic clusters. It is an opaque steel-gray to silver-white, with a metallic lustre and a black streak...
    
     (Co,Fe)AsS
• Cobaltite group
  • Cobaltite
    Cobaltite
    Cobaltite is a sulfosalt mineral composed of cobalt, arsenic and sulfur, CoAsS. It contains up to 10 percent iron and variable amounts of nickel. Structurally it resembles pyrite with one of the sulfur atoms replaced by an arsenic atom....
    
     CoAsS
  • Gersdorffite
    Gersdorffite
    Gersdorffite is a nickel arsenic sulfide mineral with formula NiAsS. It crystallizes in the isometric system showing diploidal symmetry. It occurs as euhedral to massive opaque, metallic grey-black to silver white forms. Gersdorffite belongs to a solid solution series with cobaltite, CoAsS....
    
     NiAsS
  • Ullmannite
    Ullmannite
    Ullmannite is a nickel antimony sulfide mineral with formula: NiSbS. Considerable substitution occurs with cobalt and iron in the nickel site along with bismuth and arsenic in the antimony site...
    
    (Ni,Cu,Fe)(Sb,As,Bi)S