Unger Brothers ‘Diane’ Brooch. This is an early 20th Century American Art Nouveau brooch made by Unger Brothers of Newark, NJ (1872-1910/1919). This sterling silver brooch measures 2.125 inches in Diameter. The brooch bears impressed marks for Unger Brothers, Sterling, 925. This brooch is engraved on the back ‘L N Ford’. This brooch is in excellent condition.