White to oyster-white, pearlescent Dolomite cast that really does resemble a clam given its outward texture. It is a very delicate cast of Dolomite after an unknown mineral (assumed to be calcite as listed here but never proven to my knowledge). Internally, the cast has a myriad of white, shimmering, intergrown slightly saddle-shaped, flattened rhombohedral Dolomite crystals. The white color of the Dolomite is enhanced by a coating of white, chalky, soft Calcite or more Dolomite on the exterior of the piece. The walls of the cast are 1 to 2mm thick and the overall outline and texture generally simulates a clam. Ex. Charlie Key collection with label.