Nature created its own fiber optic material long before scientists even dreamed of today's highly refined optical fiber. It is a rare, naturally-occurring mineral called ulexite. The stones are composed of thousands of tiny, parallel, hairlike crystals that transfer an image just like the coherent faceplates and light guides described elsewhere in this catalog. Ulexite often is known by the name of TV stone because of its image-transferring properties. Stones are approximately 1/2 inch (13 mm) thick and 3/4 x 3/4 inches (19 x 19 mm) across the face.