Feature Gems & Gemology, Spring 1995, Vol. 31, No. 1

Meerschaum from Eskisehir Province, Turkey

This study presents a model for the origin of the Eskisehir, Turkey, sepiolite deposits. Known as “meerschaum” in the gem trade when it occurs as compact masses (especially nodules), sepiolite is mined by local farmers using basic implements and traditional tunneling methods. The best nodules are carved into objects such as pipe bowls, bracelets, and necklaces. The sepiolite nodules occur in the Pliocene-age Imisehir conglomerates, associated with dolomite, magnesite, opal-CT, and lizardite. Fibrous in morphology, they probably formed in relatively shallow water under alkaline conditions, as a result of the replacement of magnesite gravels that were subjected to pore waters with high SiO2 concentrations.