A large 18ct gold boulder opal sapphire and diamond drop pendant necklace, rub-over set with 11ct

A large 18ct gold boulder opal sapphire and diamond drop pendant necklace, rub-over set with 11ct pear cabochon opal, 0.5ct round-cut sapphire and modern round brilliant-cut diamond bale, on 18ct fine flat curb link chain, pendant 50.6mm, chain 44cm, 10gNo damage or repair, all stones present, opal has a very good play of colour with mostly greens blues and yellows, no broken links, clasp working, stamped 18ct and 750