Also (7 zaphara, saffera), 9 saffre, saffer, (zaffra, suphara). [ad. It. zaffera (Neri) or F. zafre, safre (12–13th c.); cf. Sp. zafre, safre, G. zaffer, zaffra: of uncertain origin.] An impure oxide of cobalt, obtained by roasting cobalt-ore, and used in the preparation of smalt and as a blue coloring-matter (cobalt blue) for pottery, glass, etc.
1662. Merrett, trans. Neri’s Art of Glass, xii. Take Zaffer in gross pieces.
1686. Phil. Trans., XVI. 26. Smalt is made of Zaffer and Pot-ashes.
1693. trans. Blancard’s Phys. Dict. (ed. 2), Zaphara or Saffera.
1745. Watson, in Phil. Trans., XLIII. 497. Zaffer, which is used by the Glass-makers and Enamellers, is made of Cobalt … calcined after the subliming the Flowers.
1804. trans. Tingry’s Paint. & Varn. Guide, 301. Smalt, or vitreous oxide of cobalt, is saffer reduced to blue glass by the action of a violent fire.
1843. Poe, Tales, Gold. Bug. Zaffre, digested in aqua regia, and diluted with four times its weight of water, is sometimes employed; a green tint results.
1912. M. Ohnefalsch-Richter, in Contemp. Rev., Dec., 860. The Egyptian porcelain and faïence manufacturer, who used for the zaffre the Cyprus blue-stone.
