Vintage Modernist Carved Brooch, Black Stone, Obsidian, Silver Metal.

A vintage (late 50’s?) brooch in a modernist / brutalist style with a heavily textured silver coloured metal setting and and oval glass-like black stone carved with zigzags. I think the stone might be obsidian or black onyx - it’s dense and glossy.

CONDITION - a little dust and slight patination to the metal, and the tiniest scuff to the stone (scarcely visible and possibly a natural variation in the stone - top left, please see pics). Secure pin with roll over catch

MEASUREMENTS- overall size 4.7cm by 3cm, stone 2cm by 2.5cm