Minerals and Metals in Ancient India v2.c47.62

v2.c47.62

*Sunstone* is a variety of oligoclase, Na-Ca feldspar containing little K and Ba feldspar. A play of colour is a common character, fire-red, yellow, blue, green etc. This is due to interference of light, caused by reflection from thin lamellar inclusions of various minerals such as hematite, goethite etc. Associated with granite and igneous rocks.