A Victorian sapphire and diamond crescent brooch

seven graduating old brilliant cut diamonds, diameter from approximately 1.1 to 3mm, estimated approximate total weight 0.38ct, further set with four oval faceted sapphires, estimated approximate total weight 0.40ct, pierced scalloped border with beaded decoration, diameter 3cm, pin and hook fitting with safety chain, unhallmarked, stamped ‘15’, weight 7.4g