Art Deco black opal and diamond brooch. A glorious glowing black opal, displaying an entrancing palette of colors with the emphasis on blue, green and yellow, is elegantly presented in a geometric platinum frame containing thirty straight baguette diamonds totaling 4.00 carats. The surface of the opal displays mild crazing or checking. This unique and majestic Art Deco brooch measures 1 3/4 inches by 13/16 inch.