from
The Collaborative International Dictionary of English v.0.48
Ultramarine \Ul`tra*ma*rine"\, 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]