Johann Conrad Geiss ( 1771-1846 ) was a pioneer of many innovative techniques in casting and his ideas were widely copied.
Cast-iron jewellery was an inexpensive but fashionable novelty for consumers in Europe and America from around 1800 to 1860. Developed in Germany in 1806–7 and often worn during mourning, it became the symbol of Prussian patriotism and resistance to Napoleon I in the Prussian War of Liberation fought from 1813-15. Women donated gold jewellery to their country in exchange for iron inscribed ‘I gave gold for iron’.
The transformation of cast iron, a dark metal of little value, into a fashionable product was an important Prussian manufacturing success. Factories became adept at casting small, delicate parts which could be assembled to create the jewellery. A renewed interest in the Medieval past throughout Europe brought stylistic change. After 1815, the Neo-classical designs of earlier Berlin ironwork were replaced by Gothic motifs such as the trefoil, quatrefoil, and fine pointed arches. The jewellery quickly gained an international profile. Demand peaked in the 1830s, when Berlin alone had 27 foundries and manufacture spread to France and Austria.