platinum and sapphire ring with an intaglio of a porcupine

An Art Deco platinum ring set with an octagonal cut blue natural no heat sapphire with an intaglio of a porcupine (4.5 carats) symbol of self protection and self defense, France, circa 1920.

dimensions sapphire: 10.9 x 10.8 x 2.7 mm
weight: 10.2 gram
ring size: 15.75 mm 5 US