Along a distance of more than 1000 km the banks of the Yellowstone River are offering possibilities for collecting the “Montana Agate”.
This transparent to translucent type of agate is characterized by a pale whitish colour in combination with interesting black inclusions (Mangenese-oxide). These agates are waterworn and usually completly rounded pebbles.
The inclusions are following fractures or porous layers of chalcedony. If these inclusions are giving an imagination to the viewer - such as landscapes, trees, bushes ... - than they are highly desired and sometimes very high priced.
Sometimes the Montana-agates are showing the Iris-Effect in very thin cut (>2,5 mm) slabs. “Water-level-agates” are unusual for this type of agate.
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Northamerica/USA/Montana/ Yellowstone River |