Azure spar, sometimes azur-spar, is a trivial and commercial, partly obsolete name for several of the most famous bright blue or blue-colored minerals, which also have similar names, most notably for lazurite and azurite, and also for the less commonly used lazulite.
In addition, Robert Jameson in his fundamental works of 1804-1821 also included hauyne as a separate mineral species and the so-called “calaite”, which in the 1820s meant only turquoise, among the azure feldspars.
Lazurite, old name Azure spar is a tectosilicate mineral with sulfate, sulfur and chloride with formula (Na,Ca)8[(S,Cl,SO4,OH)2|(Al6Si6O24)]. It is a feldspathoid and a member of the sodalite group. Lazurite crystallizes in the isometric system although well‐formed crystals are rare. It is usually massive and forms the bulk of the gemstone lapis lazuli.
View the full Wikipedia page for LazuriteAzurite or Azure spar is a soft, deep-blue copper mineral produced by weathering of copper ore deposits. During the early 19th century, it was also known as chessylite, after the type locality at Chessy near Lyon, France. The mineral, a basic carbonate with the chemical formula Cu3(CO3)2(OH)2, has been known since ancient times, and was mentioned in Pliny the Elder's Natural History under the Greek name kuanos (κυανός: "deep blue," root of English cyan) and the Latin name caeruleum. Copper (Cu) gives it its deep blue color.
View the full Wikipedia page for AzuriteHauyne or haüyne, also called hauynite or haüynite (/ɑːˈwiːnaɪt/ ah-WEE-nyte), old name Azure spar, is a rare tectosilicate sulfate mineral with endmember formula Na3Ca(Si3Al3)O12(SO4). As much as 5 wt % K2O may be present, and also H2O and Cl. It is a feldspathoid and a member of the sodalite group. Hauyne was first described in 1807 from samples discovered in Vesuvian lavas in Monte Somma, Italy, and was named in 1807 by Brunn-Neergard for the French crystallographer René Just Haüy (1743–1822). It is sometimes used as a gemstone.
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