On 15 May 1891, Lalique invented and patented an enamel-making process for work in any desired thickness, applicable or not to jewelry and ornamental metalwork. This is one of the patents registered by Lalique throughout his accomplished career. The process of applying layers of enamel to the glass surface demands a precisely measured brush stroke by highly skilled artisans, for example, a single vase may require a full day's work. The firing and re-firing of the object is a necessary procedure, however, it exposes the piece to the risk of breakage or deformation. Ultimately, for financial reasons, Lalique abandoned this
labor-intensive process, which explains the rarity of enamel works nowadays.

cf. Felix Marcilhac, R. Lalique, Catalogue raisonné de l'oeuvre
de verre, Les éditions de l'Amateur, Paris, ref. no. 990;
C. Vane Percy, The Glass of Lalique: a Collector's Guide, 1977, Blacker, Calmann Cooper Ltd., London, p.35; Nicholas M. Dawes, Lalique Glass, Crown Publishers Inc., NY, 1986, p.47; René Lalique exhibition catalogue, Odakyu Museum, Tokyo, 28 July-15 August 1993, p.80