The Montana Agate is usually a creamy light yellow to almost clear color with embedded moss structures in varying shades of brownish red to black. Most of these Montana Agates are found in gravel deposits from the Pleistocene age (10,000 - 1,6000,000)
It can also be known as the Yellowstone Agate because of its origin that is centralized in the Yellowstone Park area.
Montana Agate is characterized as having a red iron oxide and black manganese oxide, or as nodules of gray, semi-transparent Chalcedony.
It can be cut and polished,and it often exhibits small manganese dendrites in a pleasing form.
This type of Agate is a relatively hard rock because it mostly consists of silica (quartz).
Additionally, Montana Agate is considered one of the important state gems in Montana.
Montana Agate is also sometimes referred to as Moss Agate or Iris Agate.
The hardness of Montana Agate is significant when it comes to making jewelry because it is the hardness that can provide the stone's sparkle.