Chemical Formula: KLi2Al(F,OH)2(Si4O10)

Chemical Name: Hydrous Potassium Lithium Aluminium Silicate

Mineral Class: Phyllosilicate

Mineral Notes: Lepidolite belongs to the Mica family of phyllosilicates. It has Muscovite structure with Li 1+ ions replacing some of the Al 3+ of Muscovite. It is distinguished by the pink colouration and is one of the most important sources of the metal Lithium. When added to glass it lowers thermal expansion and thus makes the glass less likely to shatter when heated. This is the basis of Pyrex glass.

Description: Overlapping platy-crystals of Lepidolite on matrix. The colour is a very bright pink with a tinge of yellow or red. The plates are extremely lustrous, giving this specimen a very bright appearance.

Location: Hoydalen, Tordal, Telemark, Norway.