Cat's Eye Effect
The Cat's Eye Effect or chatoyance demonstrated with a single LED as a light source behind a grid of parallel wires, forming a light stripe due to the reflection of light in each wire. We can find gemstones with single bands patterns like the slits in cat’s eye, but on other gemstones, the patterns form stars with multiple rays. These beautiful optical effects are created in many cases by light reflected in beams of needle-like crystals, or light reflected in tiny hollow tubes within a crystal. More information about this image can be found in our paper "Jumping Sundogs, Cat’s Eye and Ferrofluids" https://www.mdpi.com/2410-3896/5/3/45/htm
—Alberto Tufaile, Soft Matter Lab, EACH-University of Sao Paulo, Brazil