Butte Opal Carving Depicting Sea Life by W.K. Ngai :Opal Butte, Oregon Opal Butte opal is a rare precious stone mined from the depths ofthe Opal Butte in the Blue Mountains of Oregon. This unique silica-rich opal is found within geode-like structures called thunder eggs, formed 65 million years ago by lava flow. Opal Butte is one ofthe few active precious opal mines in the world today. Depicting sea life in a vertical presentation, with a sea turtle, multiple starfish and scallop shell and stylized coral, carved from a single large specimen of orange and white opal in a matrix of brown and taupe. Raised on a base of natural coral, above a free-form base of polished black onyx. Measuring 11 x 9 x 7in (27.9 x 22.9 x 17.8cm)