Conceived in his trademark geometric style, one is a unique round brooch decorated with garlands of cabochon gemstones which is dated to 1908 (estimate €60,000-80,000).
The other, shown above, is rectangular, made of malachite and silver, dates from 1911 and belonged to the family of the Viennese sculptor Anton Sinn who was a friend of both Hoffmann and the artist Gustav Klimt.
It has an estimate of €15,000-30,000.