Wonderstone is a common name for rhyolite, a type of igneous lava formed 120 million years ago. It is composed predominantly of volcanic glass particles welded together by heat and compacted by the weight of overlying material.
Colorful banding was caused by iron oxides in circulating ground water. The striking and intricately
folded bands of color create designs in cream, yellow-brown, black, and maroon
This wonderstone was found in Nevada and Utah.