Phlogopite


Composition: KMg3AlSi3O10(OH)2
Crystal System : Monoclinic
Colours: Greyish-brown, red-brown, white, pale-green, pale-yellow, colourless
Lustre : Pearly
Hardness (H) : 2.0-2.5
Specific Gravity (S.G) : 2.76-2.90
References: Keller (1984)

Distribution

Very rare.

Occurrence

  • Supergene
  • Country Rock

Paragenetic and General Notes

Phlogopite occurs as a rock-forming mineral (in the feldspathic sandstone (?)) but also as minute white crystal aggregates on azurite (Gebhard, 1999).

Keller (1984; citing a personal communication from Olaf Medenbach) notes the occurrence of phlogpopite as a low temperature secondary mineral.