A 9ct gold mounted Chatham style emerald crystal set brooch, by Albion Croft Co Ltd, 1971, the synthetic emerald crystal group set within an abstract geometric mount with scaled finish, hallmarked for 9ct gold and bearing maker’s mark ‘ACCO’, brooch length 56mm. £300-500

Chatham emeralds are American laboratory grown synthetic emeralds, composed of the same chemical, physical and optical properties as natural emeralds.