|1.||a blue pigment consisting of sodium and aluminium silicates and some sodium sulphide, obtained by powdering natural lapis lazuli or made synthetically: used in paints, printing ink, plastics, etc|
|2.||a vivid blue colour|
|3.||of the colour ultramarine|
|4.||from across the seas|
|[C17: from Medieval Latin ultramarinus, from ultrā beyond (see |
pigment in the gem lapis lazuli, used by painters as early as the European Middle Ages. Ore containing the colour was ground, and the powdered lapis lazuli was separated from the other mineral matter. The pigment was first produced artificially in the late 1820s in France and Germany, being made from about equal amounts of china clay, sulfur, and sodium carbonate, with lesser amounts of silica and rosin or pitch. The mixture is fired slowly to 750 C (1,380 F) and cooled in a sealed furnace. Depending on the proportion of the ingredients, the shade varies from greenish to reddish blue
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