Mineralpedia Details for Kaatialaite

Named after the type locality in the Kaatiala pegmatite in Finland. Kaatialaite is a rare mineral that occurs in granite pegmatites and in oxidized silver-arsenic veins in gabbro. Additional localities include in Germany, the Czech Republic, and the United States. Associated minerals include arsenolite, lollingite, calcite, and gypsum. The water content of the mineral is variable depending on relative humidity. It will also become cloudy upon exposure to light.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/kaatialaite.pdf

Formula

Fe³⁺(H₂AsO₄)₃·3H₂O 

Crystal System

Monoclinic 

Crystal Habit

Acicular, Lath 

Color

greenish blue, gray, yellow, white 

Streak

white 

Class

Monoclinic 

Hardness

- 

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Mindat

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White spherulitic crystals to less than <0.75mm with good coverage across face associated with fine, clear blades to less tan 0.5mm of Claudetite and native Arsenic.