This present example has lost its original pin, which would have borne the maker’s signature. Its similarity with the other two brooches, and the unparalleled sophistication of its craftsmanship, make the authorship of the jewel unquestionable.
The technique of plique-à-jour enamel has long been associated with Boucheron. The enameller Charles Riffault, an accomplished exponent of the technique, created a number of jewels for the firm that were exhibited at the 1867 Exposition Universelle in Paris. A characteristic of his pieces was the vivid palette of primary colours he used such as Royal blue, red and green, examples of which can be seen in the Victoria and Albert Museum and in the Boucheron Collection. Framed in pearl-set circular or oval borders for hair pin finials or bracelet panels, they successfully evoke church rose windows. Riffault registered a patent for the technique which was transferred to Boucheron in 1872. The patent specifically mentions the use of plique-à-jour enamel for the wings of insects. Amongst the pieces singled out in Boucheron’s display at the 1878 Exposition Universelle, for which he was awarded a Grand Prix, were sumptuous ale glasses in the Persian taste decorated with these enamels.
The technique evidently continued to be used by Boucheron late into the nineteenth century, seen at its most refined when translating the ethereal quality of an insect’s wings.