Mineral Species: Mimetite

Chemical Formula: Pb5(AsO4)3Cl

Chemical Name: Lead Chloroarsenate

Mineral Class: Arsenate

Mineral Notes: Mimetite is analogous to Pyromorphite with the arsenate (AsO4) 3-, replacing the phosphate anion (PO4) 3-. Although most properties are almost the same because of this, colour can usually be used to differentiate between the two, Mimetite being yellow and Pyromorphite being green.

Description: A small specimen but nevertheless formed of superbly shaped and terminated Mimetite crystals. These sit upright upon a matrix which provides the base for the display. Several crystals have an elongated hexagonal habit and a rather unusual yellow-brown colour enhanced by a sharp glassy luster.

Location: Hat Yai, Thailand.