Kolbeckite - Encyclopedia
Class : Phosphates, arsenates, vanadates
Subclass : Hydrated phosphates
Crystal system : Monoclinic
Chemistry : ScPO4 2H2O
Rarity : Rare
Kolbeckite is an hydrated scandium phosphate. It is with thortveitite, almost the only two minerals that contain scandium. It is a rare secondary mineral of polymetallic hydrothermal veins and phosphate deposits. It was named in honor of Friedrich Ludwig Wilhelm Kolbeck, geologist at the Mining Academy of Freiberg (Germany). Kolbeckite forms small, short prismatic crystals, sometimes small lamellar individuals united into radiate aggregates. Its color is variable : ordinarily colorless to pale yellow, it becomes bright blue to gray-blue, sometimes apple green when it is impure.
Main photo : Kolbeckite from Magnet Cove, Arkansas, USA © Stephan Wolfsried
Kolbeckite in the World
Twinning
Twins are common on {100}.
Fakes and treatments
No fakes recorded for this mineral species.
Hardness : 3 to 5
Density : 2.36
Fracture : Conchoidal
Streak : White to pale green
TP : Translucent to transparent
RI : 1.572 to 1.601
Birefringence : 0.026
Optical character : Biaxial -
Pleochroism : Strong
Fluorescence : None
Solubility : Acids
Magnetism : NoneRadioactivity : None