US Dollar
Australian Dollar
Euro
CAD
Product Description
Montana Agate Unpolished Stone Slab
This lovely unpolished stone slab of Montana Agate is just 4.4 inches by 2.76 inches and 6.5 mm thick.
This agate lapidary slab weighs .20 lbs. and is shown wet in the first 4 pictures.
Please take note in the dry pictures of its internal fractures.
Semiprecious stone Montana Agate comes from Montana, near the Yellowstone River.
Montana Agate is one of the alluvial agates, it is not found in-site, but in the Flaxville gravel deposits scattered over a huge area encompassing thousands of square miles. Montana Moss Agate is found throughout the 670 mile length of the river.
The agate originally was formed as a result of volcanic activity approximately 65 million years ago.
In Montana Agate the red color is the result of iron oxide, the black and brown is the result of manganese oxide and the red and orange came from iron oxide. On very rare occasions you can get a green from copper.
It is considered a moss agate because of the mossy shape of its inclusions, but more often it is banded, polka dotted or has dendrites.
Montana Agate has been the state of Montana's official state gemstone (along with Montana Sapphire) since 1969.
