Only very few vases were produced by Lalique in black, a color apparently favored by his South American clientele. The black coloring is obtained by adding a compound of cobalt bioxide and magnesium bioxide to the glass.

cf. Felix Marcilhac, R. Lalique, Catalogue raisonné de l'oeuvre de verre, Les éditions de l'Amateur, Paris, ref. no. 920;
Catalogue, René Lalique Museum, Suwa, Japan 1992, p. 27, for an example in clear glass