Composition: Sodium-calcium aluminum silicate
Nomenclature: Named after the Greek words oligos meaning "little" and klao meaning "cleave"; because, unlike orthoclase (another variety of feldspar), the mineral does not cleave at a 90° angle.
Industrial Uses: Gemstones; ornamental stone; used in the manufacture of glass, enamel, and porcelain.
Additional Notes: A member of the Feldspar group of minerals. Sunstone is a variety of oligoclase that contains minute, aligned plates of hematite that produce a spangled, reddish reflection when the stone is turned.
Malawi : Scott 371 : 10 tambala : 20 Aug 1980
Sunstone (oligoclase feldspar)