14.5ct white opal and 18ct gold brooch. Stamped 750 weight 18.4 grams. Opal specifications. Opal cabochon cut 14.5ct 24.52 mm x 16.85 mm. Type:1. Body tone: N9 light opal. Transparency; semi translucent. Colours: red, green, blue, violet. Play of colour excellent, broad multi coloured flash. Excellent colour and intensity. Pattern: chaff pattern.