Rock crystal reverse intaglio brooch, late 19th century
Collet-set with a domed rock crystal, the reverse carved in intaglio and coloured with a design of a bullfinch on the branch of a plane tree.
Reverse intaglio rock crystal jewels became popular from around 1860, initially manufactured by the Belgian artist Emile Marius Prader, and in England most notably by the lapidary Thomas Cook and his student Thomas Bean. These unusual jewels were extremely labour intensive. A miniaturist would paint a design in watercolour on the reverse of a hand polished rock crystal cabochon, and then a specialised lapidary would carve the design in intaglio into the rock crystal. Finally, the intaglio's surface would be painstakingly applied with oil paint in order to faithfully recreate the miniaturist's design, before the back would be sealed and the piece set by a jeweller.
So skilful were these miniature designs that in England they were initially assumed to be the work of the renowned contemporary enamel miniaturist William Essex (1784-1869). Though Essex had no involvement in the medium's development, these distinctive pieces became known as 'Essex Crystal', an erroneous name that is still in use today.
The present piece, with its design of a bullfinch upon the branch of a plane tree, is representative of the natural themes popular in this medium, and in particular the three-dimensional branch of the plane tree jutting forward into the rock crystal demonstrates the extraordinary heights of technical virtuosity that were achieved by these distinctive jewels.