Yellowstone National Park has a mountainside containing obsidian between Mammoth Hot Springs and the Norris Geyser Basin , and deposits can be found in many other western US states including Arizona , Colorado , Texas , Utah , Oregon and Idaho . Yellowstone National Park has a mountainside containing obsidian located between Mammoth Hot Springs and the Norris Geyser Basin , and deposits can be found in many other western U.S. states including Arizona , Colorado , New Mexico , Texas , Utah , Washington , Oregon and Idaho .