Sycamore ,a platanus variety, it is often opalized and shows the typical zigzag patterns when is cut on a certain angle. It is found in various state of North America and the geological period is Cretaceous –Eocene .
This piece here comes from Oregon, but is also found in Wyoming, Utah, California and other states.
Size: 32.2x32.2x4 mm.
Weight: 33.05 ct.