Art Deco jade, platinum & 18ct white gold brooch marked 18ct Plat H?Bros. Possibly Australian unascribed mark Hs Bros Approx cabochon size 17.5 x 12.5, with small old cut diamonds supporters, weight 5.28 grams. Tested as natural jadeite jade, marked 18ct Plat H?Bros. Possibly Australian unascribed mark Hs Bros Approx cabochon size 17.5 x 12.5, with small old cut diamonds supporters, weight 5.28 grams. Tested as natural jadeite jade