Place your TV rock on any printed surface and watch how the tiny fibers transmit the image to the top of the rock. This unusual effect is the result of ulexites amazing fiber optic properties. Try placing your rock on an actual TV screen, a photograph or a leaf. You'll see the same effect. Get them while they last! More info: Ulexite (NaCaB5O9·8H2O) (hydrated sodium calcium borate hydroxide) is a mineral occurring in silky white rounded crystalline masses or in parallel fibers. It was named after the 19th century German chemist G. L. Ulex who first discovered it. Recommended for ages 7 and older.