Natural turquoise has been subjected to dyeing and three types of impregnation.

The properties of petrified woods originating from various localities in Thailand and Myanmar are examined.

Two quartz specimens showing asterism and cross-shaped inclusions are analyzed.

An emerald reportedly from Madagascar is cut to show asterism, a rare phenomenon in this material.

A green cabochon from China resembling jadeite is found to be antigorite, a member of the serpentine group.