- lapis lazuli
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/lap"is laz"oo lee, -luy', laz"yoo-, lazh"oo-/1. a deep-blue mineral composed mainly of lazurite with smaller quantities of other minerals, used mainly as a gem or as a pigment.
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Semiprecious stone valued for its deep-blue colour caused by the presence of the mineral lazurite, which is the source of the pigment ultramarine.Lapis lazuli is not a single mineral but an intergrowth lazurite with calcite, pyroxene, and commonly small grains of pyrite. The most important mines are in Afghanistan and Chile. Much of what is sold as lapis is an artificially dyed jasper from Germany that shows colourless specks of clear, crystallized quartz and never the goldlike flecks of pyrite that are characteristic of lapis lazuli.* * *
▪ gemstonesemiprecious stone valued for its deep blue colour. The source of the pigment ultramarine (q.v.), it is not a mineral but a rock coloured by lazurite (see sodalite). In addition to the sodalite minerals in lapis lazuli, small amounts of white calcite and of pyrite crystals are usually present. Diopside, amphibole, feldspar, mica, apatite, titanite (sphene), and zircon may also occur.Because lapis is a rock of varying composition, its physical properties are variable. It usually occurs in crystalline limestones and is a product of contact metamorphism. The most important sources are the mines in Badakhshan, northeastern Afghanistan, and those near Ovalle, Chile, where it is usually pale rather than deep blue. Much of the material that is sold as lapis is an artificially coloured jasper from Germany that shows colourless specks of clear, crystallized quartz and never the goldlike flecks of pyrite that are characteristic of lapis lazuli and have been compared with stars in the sky.* * *
Universalium. 2010.
