Obsidian Dome is a glassy rhyolite (obsidian) dome easily accessible from highway 395 in eastern California. Most Californians are familiar with obsidian, having seen Native American tools and projectile points made from it in museums. Many of us have even come across nodules and chunks of it while hiking in the right areas. Rarely is it encountered in such tremendous blocks and boulders such as those that abound in the piedmont around the base of this particular dome. Its a really beautiful sight.