2.7" Botryoidal Prehnite On Epidote - Mali
This is a 2.7" wide association of translucent, botryoidal green prehnite with dark-green epidote, collected from the Kayes Region of Mali, Africa.
Prehnite is a calcium aluminum silicate with the chemical composition Ca2Al(AlSi3O10)(OH)2. It generally occurs as volcanic cavity infillings, and typically is a shade between yellow and green, however colorless and blue specimens are not unheard of.
Epidote is a green, silicate mineral that is commonly found in regionally metamorphosed rocks. It often forms lustrous, elongated and interconnected crystals that are highly coveted by collectors. While nearly all epidote is green it may take on many different shades and tones from yellowish to deep green.