THE MINERAL AUSTINITE

• Chemistry: CaZnAsO4OH, Calcium Zinc Arsenate Hydroxide
• Class: The Phosphates
• Subclass: Arsenates
• Group: Adelite
• Uses: Only as mineral specimens.
• Specimens

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Austinite 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 can have a very nice color and silky or sub-adamantine (almost gem-like) luster. Fine specimens occur as radial clusters of intensely green crystals, and are much in demand.

Austinite is named after the mineralogist Austin F. Rogers.

PHYSICAL CHARACTERISTICS:

• Color is typically a bright green, but also colorless, white or pale yellow.
• Luster is sub-adamantine or silky.
• Transparency: Crystals are transparent to translucent.
• Crystal System is orthorhombic; 2/m 2/m 2/m
• Crystal Habits include acicular or bladed crystals in druses, radial aggregates or crusts, also fibrous.
• Cleavage is perfect in one direction lengthwise.
• Fracture is uneven.
• Hardness is 4 - 4.5.
• Specific Gravity is approximately 4.1 (heavy for translucent minerals)
• Streak is white to pale green.
• Associated Minerals are adamite, legrandite, limonite, smithsonite, aragonite and other oxidation zone minerals.
• Notable Occurrences include Mapimi, Mexico; Tsumeb, Namibia and Toole Co., Utah, USA.
• Best Field Indicators are crystal habit, cleavage, color, luster, density, lack of fluorescence and associations.