Austinite

Austinite
Austinite from the Ojuela Mine, Mexico
General
CategoryArsenate minerals
Formula
(repeating unit)
CaZnAsO4(OH)
IMA symbolAus[1]
Strunz classification8.BH.35
Dana classification41.5.1.3
Crystal systemOrthorhombic
Crystal classDisphenoidal (222)
H-M symbol: (2 2 2)
Space groupP212121[2]
Unit cella = 7.43, b = 9.00
c = 5.90 [Å], Z = 4[3]
Identification
Formula mass261.38 g/mol
ColorColourless, white to pale yellowish-white or bright green, colourless in transmitted light[4]
Crystal habitWell developed orthorhombic crystals of bladed or acicular habit elongated parallel to the c axis, sometimes with sceptre-like terminations, also radially fibrous crusts and nodules. Common forms are {110}, {111}, {1–11}, {010} and {011}.[2]
TwinningLeft- and right-handed individuals joined on {100}, with {010} and {001} coincident.[5]
CleavageGood in two directions parallel to the prism faces {110}[2]
TenacityBrittle
Mohs scale hardness4 to 4.5
LusterSubadamantine to silky in fibrous aggregates
StreakWhite
DiaphaneityTranslucent to transparent
Specific gravity4.12
Optical propertiesBiaxial (+)
Refractive indexnα = 1.759, nβ = 1.763, nγ = 1.783,
Birefringence0.024[2]
2V angle47°[2]
Dispersionr > v weak
SolubilityEasily soluble in cold dilute HCl[2]
Other characteristicsNon-radioactive. Some austinite fluoresces green under SWUV.
References[4][6]

Austinite is a member of the adelite-descloizite group, adelite subgroup, the zinc (Zn) end member of the copper-Zn series with conichalcite. It is the zinc analogue of cobaltaustinite and nickelaustinite.[4] At one time “brickerite” was thought to be a different species, but it is now considered to be identical to austinite.[7] Austinite is named in honour of Austin Flint Rogers (1877–1957), American mineralogist from Stanford University, California, US.

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b c d e f L. W. Staples (1935). "Austinite, a new arsenate mineral, from Gold Hill, Utah" (PDF). American Mineralogist. 20: 112–119.
  3. ^ Wallace E. Richmond (1940). "Crystal chemistry of the phosphates, arsenates and vanadates of the type A2XO4(Z)" (PDF). American Mineralogist. 25: 441.
  4. ^ a b c Austinite: Austinite mineral information and data. Mindat.org. Retrieved on 2011-10-09.
  5. ^ Sidney A. Williams and Julie de Azevedo (1967). "Austinite from Gold Hill, Utah" (PDF). American Mineralogist. 52: 1224–1226.
  6. ^ Austinite Mineral Data. Webmineral.com. Retrieved on 2011-10-09.
  7. ^ Wolfgang Brendler (1938). "On the identity of austinite and brickerite" (PDF). American Mineralogist. 23: 347.