Ca₃Mg(SiO₄)₂

This sample of merwinite is displayed in the Smithsonian Museum of Natural History. Merwinite is a silicate mineral with the composition Ca₃Mg(SiO₄)₂. The sample at left is about 8 cm and is part of the collection of Cretaceous Period minerals from Crestmore, California. It is described as merwinite with blue calcite.