Ceylonese Blue Moonstone. Moonstone, though not particularly tough or durable, has been appreciated since ancient times because of its sheen and its ghostly, moon-like whiteness. The present biggest commercial source of the gemstone is India, and AGrade Indian Moonstone can be very attractive, quite translucent, with an excellent sheen and with a cat’s eye effect, a diffused line inside the gemstone that responds to the light source, but it very rarely possesses the blue tinge of the Ceylonese Blue Moonstone.
Sri Lanka’s mines are still  producing this bluish translucent gemstone, but it has become distinctly more difficult, and consequently more costly, to source.