About Montana Moss Agate
Montana moss agate is a special type of agate or patterned cryptocrystalline quartz which displays black, brown and red dendritic or plant-like formations in their banding. There's no real moss in a Montana moss agate
Montana Moss agates are only found in and around the Yellowstone River and it's tributaries between Sidney and Billings flowing north east to the Missouri river.
Natives of the region worked the material into arrowheads and other tools and its believed to first be cut and polished starting in 1914.