Minerals and Metals in Ancient India v2.c43.s3.t10.2

v2.c43.s3.t10.2

Moonstone, available in Sri Lanka, is a microperthitic to sub-microperthitic intergrowth of orthoclase and albite in an arrangement of thin layers exhibiting a pearly opalescent reflection or shiller or a delicate play of colours. It has a beautiful blue bloom and lovely sheen. Sunstone is a variety of oligoclase, Na-Ca feldspar containing little K and Ba feldspar. A play of colour (fire-red, yellow, blue, green etc.) is a common characteristic of sunstone; this is due to interference of light, caused by reflection from thin lamellar inclusions of various minerals such as hematite, goethite etc. Usually this mineral is associated with igneous rock.