Moonstones

Part of speech: noun

Definitions

1. A type of gemstone characterized by its unique optical phenomenon, resembling a glowing light under certain angles
2. A naturally occurring mineral known for its adularescence, often used in jewelry for its captivating sheen
3. A form of feldspar that exhibits a billowing luminescence, prized for its aesthetic appeal in ornamental crafts

Etymology: "Moonstones" is the plural of "moonstone", a word made by joining "moon" and "stone" into a single compound. The name describes the gem's appearance: its pale, milky sheen seems to float just beneath the surface, like light on the moon. Where the stone is cut as a cabochon, that glow moves across the curved face as the gem is turned, which is why the name fits so well. Because the word is a plain compound, its history is simple. Both parts are old English words, and the combination describes the stone directly rather than borrowing a term from another language. The plural simply adds the usual "-s" to the noun.