另附:有关斯里兰卡月长石的资料中的一个片段:
In this large rough moonstone we can see the spectacular blue sheen. Its origin is due to alternate layers of albite and orthoclase feldspar. This piece is sadly not gem quality as it has a lot of inclusion. This stone is very representative of the material find nowadays in the deep of metiyagoda mine. The upper layers that were mined during the last 50 years were producing some much more clean material. This is the reason why the large wonderful moonstones from the past are not anymore available.

Photo : Vincent Pardieu, 2005