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Montana Agate Rock slab 39

  • 2195


Montana agate has been a long time favorite of the lapidary enthusiast. Found in the alluvial gravels of the Yellowstone River in eastern Montana it has been collected and worked as a semiprecious stone for nearly a century. Noted for its clarity as well as its characteristic isolated black, and occasionally bright red dendrites, it makes excellent cabbing material. The majority of Montana agate pieces show a well-defined fortification pattern of black and brown as well as bright red/orange. There are also variations of filament and tube patterns and a small percentage display an “iris” band in which minute, regularly spaced layers act as a diffusion grating and, like a prism, break light into a rainbow of color. It is a relatively easy material to work with, being quite hard, and takes a brilliant polish.

Origin:  Montana, US

Dimensions:  3" x 1.5" and approximately 6.5 mm thick.  Weight = 49 g.  

Shown wet.  Not polished.  No significant flaws.


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