This is a vintage HEAVY sterling silver and citrine or cairngorm brooch from Scotland and has a locking clasp plus safety chain - in very good condition - size is 52mms in diameter and weighs a heavy 17.8 grams. The citrines are slightly different shades as per photos.
This brooch is fully hallmarked for Glasgow 1955 and stamped with makers mark "RA" for Robert Allison.