Mineral Species: Biotite

Chemical Formula: K(Fe,Mg)2(Si3Al)O10(OH)2

Chemical Name: Potassium Magnesium-Iron Aluminium Silicate

Mineral Class: Phyllosilicate

Mineral Notes: Biotite is a common rock forming mineral, being present in at least some percentage in most igneous and both regional and contact metamorphic rocks. It belongs to the Mica sub-class characterised by cleavage into thin sheets.

Description: Small, platy crystals of Biotite embedded in Feldspar. The mineral has a strong bronze colour and sharp glassy lsuter. The contrast with the white Feldspar is very attractive.

Location: Tripp Mine, Cardiff Township, Haliburton Co., Ontario, Canada