25 Moss agate pendants from India with silver pin and eye.

Moss agate is a semi-precious stone. The stone gets its name from the greenish inclusions (drawings) that resemble moss. Moss agate is a variety of agate. The white background of the moss agate consists of quartz. The dendritic inclusions are chlorite or iron and manganese minerals which have a great resemblance to moss. Depending on the valence of the metal, the inclusions show different colors. Moss agate therefore contains no organic material despite the name. 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 variants of quartz. The green/blue/red/yellow and brown stones are polished/cut used for jewelry or as a talisman. The most important sites of moss agate are India, China, the US and occasionally in South Africa and Brazil. Moss agate is found in the US, among other places, in the deposits of the Yellowstone River and its tributaries, between Sidney (Montana) and Billings (Montana). In this variant, called Montana moss agate, the red color is caused by iron(III) oxide (rust) and the black by manganese(IV) oxide.