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

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

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

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

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