Montana Moss Agate Treasures

Montana Moss Agate is the name given to the beautiful chalcedony found in the alluvial gavels of the Yellowstone River and its tributaries. It is From the Pleistocene age (10,000 - 1,6000,000) Found not in-site, but in gravel deposits.


A small area in Montana seems to have the best of this agate. Found in gravel deposits in the middle and lower Yellowstone valleys. Agates are found in both the present stream bed and in gravel terraces. 10 to 15 miles either side of the Yellowstone drainage. 

Rough                                                    Polished













Cabochons Jim has made from Montana Moss Agate