gold and tourmaline ring

An 18 carat gold ribbed ring, set with an oval cabochon cut pink tourmaline, signed and numbered: Van Cleef & Arpels, 8587814.
France, circa 1980.

ring size: 16 mm. 5½ US
weight: 11.3 grams
dimensions tourmaline: 9.3 x 8 mm.
shank: 4 – 12 mm.