Polka Dot Agate; found near Madras in Central Oregon, a highly mineralized chalcedony whose popularity goes back to ancient times. The whitish, bluish, and reddish chalcedony is riddled with hematite dots in mostly browns and yellows. These dots, accompanied by multicolored patterns, resemble moons or other lunar bodies. The beautiful patterns and colorful landscape scenes in this material produce fantastic finished pieces.You can test your imagination with this material.