Oregon Polka-Dot Agate, found near the Polka Dot mine in the Central Oregon desert, is famous for its translucent chalcedony sprinkled with naturally occurring “dots” of red, yellow, or blue from iron and manganese inclusions. Each piece looks like abstract art formed in volcanic rhyolite flows millions of years ago, making it a favorite among lapidary artists for its painterly patterns. The mine has been closed. This piece was collected, cut and polished by Passingstones.