Duette Marcasite 1950's Double Clip Brooch

The Duette brooch was an important jewellery accessory patented first by Cartier in the 1920's followed by the American Company Coro who patented their own design in 1935.  They went on to be popular and be produced by a small number of costume jewellery companies until the 1950's.   I believe this to be a 1950's piece - a time when marcasite became very popular. It is in perfect condition with all stones present and set in silver tone metal. It has a framework with two halves of the clip attached to wear as a brooch, and can also be separated to wear as two dress clips, hat clips, shoe clips etc. The clip mechanism separates easily and is easily put back together again. A lovely nostalgic piece gift boxed by Vintageonline measuring 6cms x 2.5cms.