Long thin triangle shaped milky translucent with black semi precious gemstone Montana Agate designer cabochon 43 mm by 9 mm and 3 mm thick.
Pretty semi precious gemstone Montana Agate comes from near the Yellowstone River in Montana.
In Montana Agate cabochons the red color is the result of iron oxide, the black is the result of manganese oxide. It is considered a moss agate.
Agate is a microcrystalline Quartz and has a hardness of 7, which makes the Montana Agate designer cabochons very wearable.
Montana Agate has been the state of Montana's official state gemstone (along with Montana Sapphire) since 1969.