A grouping of muscovite crystals with a sandwich appearance, due to the much darker cores, with very dark smoky quartz penetrating in several areas. Point of attachment was the bottom. No damage. Ex Ken Roberts collection. Locality: Dogtooth Peak, Fresno County California Composition: phyllosilicate mineral of aluminium and potassium KAl₂(F, OH)₂, or (KF)₂(Al₂O₃)₃(SiO₂)₆
