A gorgeous moonstone cabochon is luminescent and in different lighting will give off the colors of the amethysts and the peridot below it. Marked "925" on the back, and measures 1 inch each way. The 18 inch silver chain is marked "FNA" and "925 Italy" Please let me know at purchase if you'd like me to polish the silver. Some folks like the old patina, and some don't. The moonstone is the third eye chakra and is said to balance emotions, bring good fortune, and protect at land and sea.