Kaatialaite: Properties and Occurrences

Kaatialaite [Fe(H2AsO4)3·5H2O] is a ferric arsenate mineral found in Finland. It is a ferric arsenate mineral. It was named after the type locality in the Kaatiala pegmatite in Finland. It is a rare mineral that occurs in granite pegmatites and in oxidized silver-arsenic veins in gabbro. Additional localities including in Germany, the Czech Republic, and the United States.

General Information

  • Category: Arsenate mineral
  • Formula: [Fe(H2AsO4)35H2O]
  • Crystal system: Monoclinic (Unknown space group)
  • Kaatialaite is Not Radioactive

Fig: Kaatialaite


The water content of the mineral is variable depending on relative humidity. It will also become cloudy upon exposure to light. Associated minerals include arsenolite, lollingite, calcite, and gypsum.

  • Color: Greenish blue, gray, yellow, white
  • Streak: White
  • Diaphaneity: Transparent
  • Specific Gravity: 2.64
  • Luster: Earthy
  • Transparency: Translucent

Occurrence: A secondary mineral in a granite pegmatite (Kaatiala pegmatite, Finland); in an oxidized Ag–As vein in gabbro (Niederbeerbach, Germany).

Association: Arsenolite, l¨ollingite, calcite, gypsum (Kaatiala pegmatite, Finland).


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