Olgite: Properties and Occurrences

Olgite is a rare blue-green colored phosphate mineral series that forms microscopic prismatic crystals that are trigonal in structure. It is a trigonal-hexagonal scalenohedral mineral containing barium, oxygen, phosphorus, sodium, and strontium. Its chemical formula is Na(Sr, Ba)PO4.

General information

  • Formula: Na(Sr,Ba)PO4
  • Colour: Bright blue, bluish green
  • Hardness: 4½
  • Specific Gravity: 3.94
  • Crystal System: Trigonal

Properties

A mineral is an inorganic crystalline solid, natural, homogeneous, with a structure and a composition that gives it defined macroscopic properties. Olgite is that mineral is (mineralogy) a trigonal-hexagonal scalenohedral mineral containing barium, oxygen, phosphorus, sodium, and strontium.

  • Lustre: Vitreous
  • Transparency: Translucent
  • Hardness: 4½ on Mohs scale
  • Tenacity: Brittle
  • Cleavage: None Observed
  • Fracture: Irregular/Uneven
  • Density: 3.94 g/cm3 (Measured) and 3.904 g/cm3 (Calculated)

Occurrence: In nepheline syenite pegmatite in a differentiated alkalic massif.

Olgite was discredited as a mineral name in 2008 by the International Mineralogical Association and is now the series name for bario-olgite and strontio-olgite (hypothetical mineral). The substance was named after Russian mineralogist Olga Anisimovne-Vorobiova (1902–1974).

Association: Natrosilite, analcime.