Mineral Species: Celadonite

Chemical Formula: K(Mg;Fe2+)(Fe3+;Al)Si4O10(OH)2

Chemical Name: Potassium Magnesium Iron Aluminium Silicate Hydroxide

Mineral Class: Phyllosilicate

Mineral Notes: Celadonite replaces primary ferromagnesian silicate minerals in altered intermediate to mafic volcanic rocks, developed under low-grade zeolite facies metamorphism. Also as amygdule fillings in basalts or andesites. It belongs to the Mica group. The mineral is named from the French 'celadon', for sea green, reflecting its common colour.

Description: A pale grey Orthoclase matrix in which are embedded tiny flaky crystals of green Celadonite. Although these look amorphous, magnification shows a very distinct crystal structure, high glassy luster and the attractive green colour. When carefully observed a very clear sheet-like crystal form can be seen which is characterisitc of mica group minerals.

Location: Vezna, Czech Republic.