Geographic Minerals

Fabianite: Properties and Occurrences

Fabianite: Properties and Occurrences

Fabianite is a borate mineral with the chemical formula CaB3O5(OH). It is a monoclinic-prismatic colorless mineral containing boron, calcium, hydrogen, and oxygen. It was named for Hans-Joachim Fabian, a German geologist. It is not radioactive.

General Information

  • Category: Phylloborates
  • Formula: CaB3O5(OH)
  • Crystal system: Monoclinic
  • Crystal class: Prismatic (2/m)


It is colorless and leaves a white streak. Its crystals are monoclinic prismatic. It is transparent and fluorescent. It has a vitreous luster. It is not radioactive. Fabianite is rated 6 on the Mohs Scale.

  • Cleavage:{011} Indistinct
  • Color: Colorless.
  • Density: 2.77
  • Diaphaneity: Transparent
  • Hardness: 6 – Orthoclase
  • Luminescence: Fluorescent, Short UV=brownish yellow, Long UV=brownish yellow.
  • Luster: Vitreous (Glassy)
  • Streak: white

No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Occurrence: In a marine evaporite deposit.

Association: Halite, anhydrite, howlite, szaib´elyite.


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