Austinite crystals (white) forming a crust on Adamite crystals from Mexico.
CHEMISTRY - CaZn(As4)(OH)
CRYSTALLOGRAPHY - Orthorhombic
CRYSTAL GROWTH AND HABITS - Austinite forms crusts of bladed crystals, sometimes fibrous or nodular.
COLOR AND OPTICAL PROPERTIES - Colorless, white to pale yellow, sometime green. Translucent to transparent.
HARDNESS - 4 - 4.5
SPECIFIC GRAVITY - 4.1 - 4.3
LUSTER - Sub adamantine to silky in aggregates
STREAK - White
BREAKABILITY - Good cleavage on {001}. Brittle
OCCURRENCE - Austinite is a rare mineral that forms in the oxidized zone of arsenic bearing minerals.
ASSOCIATED MINERALS - Adamite, Limonite, Quartz, Talmessite.