Oregon sunstone is mined in two broad areas of the state more than 100 miles apart: the Ponderosa mine in Harney County, in central-eastern Oregon, and the Plush mining area in Lake County, southwest of the Ponderosa.
An extensive study of the Ponderosa mine sunstone labradorite has revealed a number of distinctive characteristics, including aventurescence and pleochroism, as well as provided information to help determine the cause of the different colors. This sunstone can be readily identified on the basis of its gemological properties.