Ulexite, or TV rock
How to transmit images with ulexite
Can a stone translate images like a TV? Ulexite can!
Reagents and equipment
- a flashlight;
- a piece of paper with an image or writing.
Take a paper with an image (or writing) and put ulexite on top. Watch how the image is being translated onto the surface of the stone. Point the flashlight along the ulexite fibers. Watch how the stone passes light along its fibers, but not across!
Ulexite is a mineral with a fibrous structure. Its chemical formula is NaCa[B₅O₆(OH)₆] • 5 H₂O. Ulexite isn’t transparent by itself, but it can “translate images through.” If you were to place a ulexite stone on top of a text line, the letters would come through and appear on the surface of the stone. Light is conducted by its fibers thanks to inner reflection — so that the image is translated onto the other side of the stone. Due to this optical phenomenon, ulexite is also called a “TV rock.” A similar effect occurs in an optical fiber. Commercially, ulexite ore is also important as a source of boron.