n. [ L. amarus bitter. ] (Chem.) A characteristic crystalline substance, obtained from oil of bitter almonds. [ 1913 Webster ]

n. (Min.) A transparent, pale green variety of beryl, used as a gem. See Beryl. [ 1913 Webster ]

a. [ Pref. ultra- + marine. ] Situated or being beyond the sea. Burke. [ 1913 Webster ]

n. [ Cf. Sp. ultramarino. So called because the lapis lazuli was originally brought from beyond the sea, -- from Asia. ] (Chem.) 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, colored blue by the sodium polysulphides made in the fusion. Also used adjectively. [ 1913 Webster ]

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
Ultramarine ashes (Paint.), 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 than that produced by the mixture of more positive colors. Fairholt. [ 1913 Webster ]