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Lapis lazuli (UK: / ˌ l æ p ɪ s ˈ l æ z (j) ʊ l i, ˈ l æ ʒ ʊ-,-ˌ l i /; US: / ˈ l æ z (j) ə l i, ˈ l æ ʒ ə-,-ˌ l i /), or lapis for short, is a deep-blue metamorphic rock used as a semi-precious stone that has been prized since antiquity for its intense color.
More than others, lazurite or lapis lazuli has historically had a decorative use, classified by A. Fersman and M. Bauer as a first-order semi-precious ornamental stone. Haüyne is valued significantly higher than lapis lazuli, but it is rarely found in jewelry quality suitable for cutting.
Lazurite is a pigment (opalescent) and has a bright blue streak (especially as a component of the semiprecious stone lapis lazuli). Many hauynes have a white or pale blue streak and are translucent. Many hauynes have a white or pale blue streak and are translucent.
Lapis lazuli (the pigment ultramarine) was chiefly supplied from Afghanistan during the Middle Ages, whereas azurite was a common mineral in Europe at the time. Sizable deposits were found near Lyons, France. It was mined since the 12th century in Saxony, in the silver mines located there. [17]
Crystal aggregate (lapis lazuli from Afghanistan) In geology, particularly in mineralogy and petrology, an aggregate is a mass of mineral crystals, mineraloid particles or rock particles. [1] [2] Examples are dolomite, which is an aggregate of crystals of the mineral dolomite, [3] and rock gypsum, an aggregate of crystals of the mineral gypsum. [4]
Diopside is a monoclinic pyroxene mineral with composition MgCaSi 2 O 6.It forms complete solid solution series with hedenbergite (FeCaSi 2 O 6) and augite, and partial solid solutions with orthopyroxene and pigeonite.
Lazulite or Azure spar [6]: 14 is a transparent to semi-opaque, blue mineral that is a phosphate of magnesium, iron, and aluminium, with the chemical formula (Mg,Fe 2+)Al 2 (PO 4) 2 (OH) 2. [3]
Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism.