Vintage 1950's Countess Cissy Zoltowska CIS Orange Glass Brooch

Vintage 1950’s Countess Cissy Zoltowska or CIS glass brooch in good condition.
The countess was born in Vienna, she began her design career in 1951, handpainting buttons & cufflinks, but progressed quickly into designing her own style of jewellery. By the mid fifties she was working for Pierre Balmain & Jacques Fath, after which she created jewellery for Balenciaga. Pieces were rarely signed, but this piece is signed just under the clip "CIS" with a crown above. The majority of her costume jewellery designs were large statement pieces & this is no exception. 
Approximate Measurements: Length 2”, Width 2.5”
Made in France