Explaining The Universe on Instagram: "Ulexite is a soft, fibrous borate mineral best known for its natural “fiber-optic” behavior. Its crystals grow in long, parallel bundles that can internally transmit light, so when the mineral is placed on top of an image, the picture appears to be projected onto its surface—earning it the nickname “TV rock.” Ulexite typically forms in dry lake beds of arid regions where boron-rich waters evaporate, leaving behind layers of sodium and calcium borates. Usual