Word Story
The term names a roughly spherical rock that looks utterly plain on the outside but holds a cavity lined with glittering mineral crystals, most commonly quartz or amethyst. A secondary, more figurative sense paints anything that appears unassuming yet conceals brilliance or beauty—like a person whose quiet exterior masks a vivid inner world. In real life, these rocks are cracked open with a hammer or a pipe cutter at tourist attractions and rock shops, revealing jagged, sparkling hollows that feel like miniature natural cathedrals. A memorable context is a state park where visitors select an unremarkable lump from a pile, then watch it split apart to expose a frost of lavender or clear crystal that has been secretly growing for millennia.