Wurtzite

Wurtzite is a zinc and iron sulfide mineral ((Zn,Fe)S), a less frequently encountered structural polymorph form of sphalerite. The iron content is variable up to eight percent.[4] It is trimorphous with matraite and sphalerite.[1]

This article is about the mineral. For the crystal structure, see Wurtzite (crystal structure).
Wurtzite
General
CategorySulfide mineral
Formula
(repeating unit)		(Zn,Fe)S
Strunz classification2.CB.45
Dana classification02.08.07.01
Crystal systemHexagonal
Crystal classDihexagonal pyramidal (6mm)
H-M symbol: (6mm)
Space groupP63mc
Structure
Jmol (3D)Interactive image
Identification
ColorBrownish black, Orange brown, Reddish brown, Black.
Crystal habitRadial clusters and colloform crusts and masses. Also as tabular crystals
Cleavage[1120] and [0001]
FractureUneven - irregular
Mohs scale hardness3.5-4
LusterResinous, brilliant submetallic on crystal faces
Streaklight brown
DiaphaneityTranslucent
Specific gravity4.09 measured, 4.10 calculated
Optical propertiesUniaxial (+)
Refractive indexnω = 2.356 nε = 2.378
Birefringenceδ = 0.022
Other characteristicsNonmagnetic, non-radioactive
References[1][2][3]

It occurs in hydrothermal deposits associated with sphalerite, pyrite, chalcopyrite, barite and marcasite. It also occurs in low-temperature clay-ironstone concretions.[1]

It was first described in 1861 for an occurrence in the San José Mine, Oruro City, Cercado Province, Oruro Department, Bolivia, and named for French chemist Charles-Adolphe Wurtz.[2] It has widespread distribution. In Europe it is reported from Příbram, Czech Republic; Hesse, Germany; and Liskeard, Cornwall, England. In the US it is reported from Litchfield County, Connecticut; Butte, Silver Bow County, Montana; at Frisco, Beaver County, Utah; and from the Joplin district, Jasper County, Missouri.[1]

Wurtzite structure

The wurtzite group includes cadmoselite (CdSe), greenockite (CdS), mátraite (ZnS), and rambergite (MnS), in addition to wurtzite.[5]

Its crystal structure is called the wurtzite crystal structure, to which it lends its name. This structure is a member of the hexagonal crystal system and consists of tetrahedrally coordinated zinc and sulfur atoms that are stacked in an ABABABABAB pattern.

Wurtzite unit cell. The grey balls represent metal atoms, and yellow balls represent sulfur or selenium atoms.

The unit cell parameters of wurtzite are (-2H polytype):[2]

  • a = b = 3.25 Å = 325 pm
  • c = 6.26 Å = 626 pm
  • V = 79.11 Å3
  • Z = 2

See also

References
  1. Handbook of Mineralogy
  2. Wurtzite at Mindat.org
  3. Wurtzite at Webmineral
  4. Palache, Charles, Harry Berman & Clifford Frondel (1944), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume I: Elements, Sulfides, Sulfosalts, Oxides. John Wiley and Sons, Inc., New York. 7th edition, revised and enlarged, pp. 226-228.
  5. Wurtzite group on Mindat.org
  • The Mineral Wurtzite
  • "Wurtzite" . New International Encyclopedia. 1905.
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