Why “cymophanous” is a great word
Having a wavy, floating light, as in certain opalescent or chatoyant gemstones. From the combining form cymo- (from Greek kyma, "wave") and -phanous (from Greek -phanēs, "showing", from phainein, "to show"). Unlike "opalescent," which suggests a milky, shifting iridescence across the spectrum, or "chatoyant," which fixes light into a single, sharp gleam like a cat's pupil, cymophanous is the quiet shimmer that moves like breath on glass—the slow, hypnotic roll of light in a moonstone, the ghostly billow captured within a cymophane, and the serene, subaqueous gleam that appears not to shine from the stone but to drift quietly within it. It is a captured tide forever at its turning.