diamond and emerald white gold ring

A white gold Art Deco ring set with a brilliant cut diamond (app. 0.5 carats) and a quatrfoil decoration around it with single cut diamonds around a half moon cut emerald in between which small kite cut emeralds and single cut diamonds in the shank.
The Netherlands, circa 1925.

weight: 3.6 grams
ring size: 17.5 -17.75 mm. 7 ¼ -7 ½ US.
diameter: 1.9 cm.