<chemistry> A blue pigment formerly obtained by powdering lapis lazuli, but now produced in large quantities by fusing together silica, alumina, soda, and sulphur, thus forming a glass, coloured blue by the sodium polysulphides made in the fusion. Also used adjectively. Green ultramarine, a green pigment obtained as a first product in the manufacture of ultramarine, into which it is changed by subsequent treatment. Ultramarine ash or ashes, a pigment which is the residuum of lapis lazuli after the ultramarine has been extracted. It was used by the old masters as a middle or neutral tint for flesh, skies, and draperies, being of a purer and tenderer gray that produced by the mixture of more positive colours. Fairholt.

Origin: Cf. Sp. Ultramarino. So called because the lapis lazuli was originally brought from beyond the sea, from Asia.

(01 Mar 1998)