Kolbeckite: Properties and Occurrences

Kolbeckite (scandium phosphate dihydrate) is a mineral with formula: ScPO4·2H2O. It is a mineral consisting of a hydrous silicate and phosphate of beryllium, aluminum, and calcium. It was discovered originally at Schmiedeberg, Saxony, Germany in 1926 and is named after Friedrich L. W. Kolbeck, a German mineralogist.

Kolbeckite is usually found as small clusters of crystals associated with other phosphate minerals.

General Information

  • Category: Phosphate minerals
  • Formula: ScPO42H2O
  • Crystal system: Monoclinic
  • Crystal class: Prismatic (2/m)
  • Streak: white.

Fig: Kolbeckite


  • Luster: Vitreous, Pearly
  • Transparency: Transparent
  • Color: Colorless, light yellow; when impure: cyan-blue, blue-gray, apple-green
  • Hardness: 3 – 5 on the Mohs scale
  • Tenacity: Brittle
  • Cleavage: Distinct/Good On {010}, distinct, on {100} and {001}, poor.
  • Fracture: Conchoidal
  • Density: 2.36 g/cm3 (Measured) and 2.35 g/cm3 (Calculated)


Kolbeckite is a rare mineral that occurs in localities in Germany, Romania, Austria, the United States, India, Russia, and Australia. It is a secondary mineral that occurs in hydrothermal metallic veins and some phosphate deposits.


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