ULTRAMARINE, a blue pigment, consisting essentially of a double silicate of aluminium and sodium with some sulphides or sulphates, and occurring in nature as a proximate component of lapis lazuli.
As early at least as the ith century the art of extracting a blue pigment from lapis lazuli was practised, and from the beginning of the 16th century this pigment began to be imported into Europe from "over the sea," as azurrum ultramarinum.
The composition of the pigment is quite similar to that of lapis lazuli; but the constitution of both is uncertain.
The mineral was probably included with selenite under Pliny's term lapis specularis.
The lapis specularis of Pliny, scattered over the Circus Maximus to produce a shining whiteness, was probably mica.