Austinite: Properties and Occurrence

Austinite is a member of the adelite-descloizite group, adelite subgroup, the Zn end member of the Cu-Zn series with conichalcite. It is fairly rare but popular collection mineral. It forms in the oxidation zone of zinc ore deposits, often with the sometimes similar looking adamite. It is the zinc analog of cobaltaustinite and nickelaustinite. At one time “brickerite” was thought to be a different species, but it is now considered to be identical to austinite. It is not radioactive

Austinite is named in honor of Austin Flint Rogers (1877–1957), American mineralogist from Stanford University, California, US.

General Information

  • Category: Arsenate minerals
  • Formula: CaZnAsO4(OH)
  • Crystal system: Orthorhombic
  • Crystal class: Disphenoidal (222).

Properties

  • Formula mass: 261.38 g/mol
  • Color: Colorless, white to pale yellowish-white or bright green, colorless in transmitted light.
  • Crystal habit: Well developed orthorhombic crystals of bladed or acicular habit elongated parallel to the c axis, sometimes with scepter-like terminations.
  • Cleavage: Good in two directions parallel to the prism faces
  • Tenacity: Brittle
  • Mohs scale hardness: 4 to 4.5
  • Luster: Subadamantine to silky in fibrous aggregates
  • Streak: White
  • Diaphaneity: Translucent to transparent
  • Specific gravity: 4.12

Occurrence

Austinite is a rare mineral in the oxidation zone of arsenic-bearing base metal deposits, where it is found developed on the coliform (pertaining to the rounded, globular texture of mineral formed by colloidal precipitation) surface of limonite or lining small cavities. It is closely associated with adamite and appears to be a later mineral. Austinite is associated with adamite, quartz, talmessite, and limonite.

Austinite is uncommon to the rare secondary mineral that occurs in oxidized arsenic-rich base metal deposits in localities in the United States, Mexico, Bolivia, Greece, Namibia, and Australia, among others. Minerals associated with Austinite include adamite, talmessite, limonite, and quartz.

 

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