Montana moss agate

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Montana Moss Agate is a gorgeous agate found in the alluvial gravels of the Yellowstone River and its tributaies between Sidney and Billings, Montana. The agate originally was formed in the Yellowstone National Park area of Wyoming as a result of volcanic activity. The conditions necessary for agate formation are the presence of silica, water from rainfall or ground water, and manganese, iron, and other mineral oxides which form the mineral banding and inclusions. In Montana Moss Agate the red color is the result of iron oxide, the black is there result of manganese oxide. The mineral laden ground water fills the voids left in the volcanic lava and as a result chalcedony in the form of agates form. Subsequent erosion and earth movement freed up the agates and they were transported to their present location in the river gravels by the action of ancient inland rivers. The agates are not as plentiful as in the past but with a little experience and patience, quality agates can still be found.

Black Moss And Red Banding

Red Banded