This is a semi-pellucid variety of quartz. The colours are arraigned in strips or bands or blended in clouds and classified accordingly as moss, ribbon, dendrite, etc. The stone, widely distributed but not very popular, is generally brown. When used for ornamental purposes it has usually been dyed artificially as the porous nature of this mineral allows it to absorb material from solution. Brownish- orange agate is known as cornelian, the green variety chrysoprase, the blue variety chalcedony and the brownish-red variety carnelian. Black agate is onyx.

Agate is used for inexpensive jewelry, ornaments and even ash- trays and precision instruments.

It is found mainly in India, Brazil, Madagascar, China, Russia and Australia.