2" Mimetite and Calcite Crystals on Limonitic Matrix - Mexico
This specimen contains yellow-gold mimetite crystal clusters with calcite on a limonitic matrix. This specimen was collected from the Santa Eulalia Mining District in Chihuahua, Mexico.
Mimetite is a lead chloro-arsenate mineral with the chemical formula of Pb5(AsO4)3Cl. Depending on conditions, during formation/replacement, arsenate radicals (As04) can be replaced by a phosphate (PO4) or vanadate (VO4) radical. This alteration is what leads to the formation of pyromorphite and vanadinite, hence why they're typically found associated with each other. Regularly ranging between red and yellow in color, mimetite can occur in a variety of structures, from small prismatic clusters and crusts, to incredible hexagonal crystals both thick and thin.