Moonstone shaping and polishing in Sri Lanka

From the archive record

A Sri Lankan Man and woman polishing moon stones at the factory. Moonstone, considered to be the most valuable variety of feldspar, is the opalescent variety of orthoclase (an opaque to transparent potassium feldspar). Its schiller or adularescence is caused by the intergrowth of two different types of feldspar, with different refractive indexes. Like labradorite, it has an opalescent quality, caused by the reflection of light from the internal structure. Moonstone is usually whitish-blue, but can be colorless, yellow, orange, gray, or even reddish. Like many gems found in Sri Lanka (formerly Ceylon) and Myanmar (formerly Burma), moonstone most often occurs as pebbles and irregular masses in gem-gravels and clay-deposits. Moonstone has been mined in these sweltering forests forever and the