Moonstone Silvertone Necklace Vintage Costume Jewelry

Vintage costume jewelry necklace, silvertone with a stone inlay that is most likely moonstone. Striking design that reminds me of an art deco style arrowhead. Chain has a lobster claw clasp and is adjustable, with 17 oval holes to help with getting a loose or tight fit. Chain is 18 inches in diameter (9 inches on each side). Lovely minimalist look. I mostly wear gold or goldtone jewelry, so am setting this one free to find a new home.