Wurtzite

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

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.

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

  • a = b = 3.82 Å = 382 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
  • "Wurzite" . New International Encyclopedia. 1905.
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