Description
Moss agate is a semi-precious stone. The stone owes its name to the greenish inclusions (patterns) that resemble moss. Moss agate is a variety of agate. The white base of moss agate consists of quartz. The dendritic inclusions are chlorite or iron and manganese minerals that bear a strong resemblance to moss. Depending on the valence of the metal, the inclusions exhibit different colors. Therefore, despite its name, moss agate contains no organic material. The stone is formed from weathered volcanic rock. The chemical structure of moss agate is identical to that of jasper, flint, and chert, all also varieties of quartz. The green/blue/red/yellow and brown stones are polished/cut and used for jewelry or as talismans. The main sources of moss agate are India, China, the United States, and occasionally South Africa and Brazil. Moss agate is found in the United States, among other places, in the deposits of the Yellowstone River and its tributaries, between Sidney, Montana, and Billings, Montana. In this variety, called Montana moss agate, the red color is caused by iron(III) oxide (rust) and the black by manganese(IV) oxide.
