View source for Azure spar

{{Infobox mineral
|image= Lazurite-195604.jpg
| caption=[[Lazurite]] ([[Badakhshan]])}}
{{Other uses|Spar (disambiguation)}}
{{Other uses|Azure (disambiguation)}}
'''Azure spar''', sometimes ''azur-spar'' ({{lang-de|Lazur spath, Blau spath}}) is a [[trivial name|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]],<ref name="kriv">''Krivovichev V. G.'' Mineralogical glossary. Scientific editor [[:uk:Булах Андрій Глібович|A. G. Bulakh]]. — St.Petersburg: St.Petersburg Univ. Publ. House. 2009. — 556 p. — ISBN 978-5-288-04863-0. ''(in Russian)''</ref>{{rp|14}} and also for the less commonly used [[lazulite]].<ref name="const">''R. A. Lidin, L. L. Andreeva, V. A. Molochko''. Constants of inorganic substances: handbook. 3rd ed., reprinted, edited by R. A. Lidin. — Moscow: Drofa, 2008. — 685 p.</ref>{{rp|248}}

In addition, [[Robert Jameson]] in his fundamental works of 1804-1821 also included [[hauyne]] as a separate [[mineral species]]<ref>The same opinion was shared by the authoritative German mineralogist [[Dietrich Ludwig Gustav Karsten|Dietrich Karsten]], who in his “Mineralogical Tables” of 1800 characterized [[hauyne]] as a azure spar ({{lang-de|Lazur Spath}}) variety (Subspecies) of prismatic [[Crystal system|syngony]].</ref> and the so-called ''“calaite”'', which in the 1820s meant only [[turquoise]], among the azure feldspars.<ref name="Edinburgh">The Edinburgh Encyclopaedia, 1st American ed., Volume 13. — J. and E. Parker edition, 1832.</ref>{{rp|571-572}}

All of the listed minerals are known primarily as ornamental stones, and have historically been used as painting [[pigment]]s and dyes for various purposes. More than others, [[lazurite]] or [[lapis lazuli]] has historically had a decorative use, classified by [[Alexander Fersman|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. [[Azurite]] or copper azure is much less often used as an ornamental stone due to its fragility and chemical instability, but this mineral has been known since ancient times as a pigment for blue tempera paint, mainly in icon painting. Finally, [[lazulite]] is sometimes used not only as an ornamental stone, but also for jewelry cutting, although finds of high-quality raw materials are too rare for its mass use. As for [[turquoise]], it has been one of the most popular ornamental and semi-precious stones since ancient times.

== Main minerals ==
* [[Lazurite]] or ''[[lapis lazuli]]'' is an opaque mineral, sodium aluminosilicate sulfate with the ideal formula Na[(AlSiO<sub>4</sub>)SO<sub>4</sub>], having a color from blue to bluish- or greenish-gray, was previously widely known as azure spar.<ref name="kriv"/>{{rp|14}}
* [[Haüyne]] or ''prismatic azure spar'' is a transparent or translucent mineral, similar to lazurite, in composition [[sodium]] and [[calcium]] aluminosilicate with the ideal formula (Na,Ca)<sub>4-8</sub>Al<sub>6</sub>Si<sub>6</sub>(O,S)<sub>24</sub>(SO<sub>4</sub>,Cl)<sub>1-2</sub> having a blue or blue color, sometimes with a greenish tint,<ref>Depending on the impurities, white, grey or yellow-red [[hauyne]] is occasionally encountered, but these varieties are not considered to be “azure feldspars”.</ref> was also known among the azure spars.<ref name="Edinburgh"/>{{rp|571}}
* [[Azurite]] or ''copper azure'' is an opaque or slightly translucent mineral, copper bicarbonate in composition with the ideal formula Cu<sub>3</sub>(СО<sub>3</sub>)<sub>2</sub>(ОН)<sub>2</sub>, having a bright blue color, one of the most common secondary minerals containing copper, also known as azure spar.<ref name="kriv"/>{{rp|14}}
* [[Lazulite]] or ''azure spar''<ref name="Brit">Encyclopaedia Britannica, Volume fifth. — Edinburgh: printed for Archibald Constable and Company, 1824.</ref>{{rp|452}} is a transparent or translucent mineral, in composition a hydrous phosphate of [[iron]], [[magnesium]] and [[aluminum]] with the ideal formula (Mg,Fe<sup>2+</sup>)Al<sub>2</sub>(OH,PO<sub>4</sub>)<sub>2</sub>, having a beautiful sky-blue, light blue or bluish color, known as azure spar.<ref name="const"/>{{rp|248}}
* [[Turquoise]] or ''kalaite''<ref name="Edinburgh"/>{{rp|571-572}} is a widely known opaque mineral, which is a hydrated [[phosphate]] of [[aluminum]] and [[copper]] with the ideal formula CuAl<sub>6</sub>[PO<sub>4</sub>]<sub>4</sub>(OH)<sub>8</sub>·5H<sub>2</sub>O, and is also included among the azure feldspars.<ref name="Brit"/>{{rp|452}}

== Azure Spars Gallery ==     
<br>
<gallery>
Lazurite-236604.jpg|{{center|[[Lazurite]]}}
Hauyne-169903.jpg|{{center|[[Hauyne]]}}
Azurite-122803.jpg|{{center|[[Azurite]]}}
Lazulite-tmix07-168a.jpg|{{center|[[Lazulite]]}}
Turchese, dal messico.JPG|{{center|[[Turquoise]]}}
</gallery>

== See also ==
* [[Feldspar]]s
* [[Satin Spar]]
* [[Blue pigments]]
* [[Hauyne]]
* [[Ultramarine]]
* [[Azurite (pigment)|Azurite]]

== References ==
{{reflist}}

{{Set index article}}
[[Category:Set index articles on minerals]]
[[Category:Pigments]]
[[Category:Carbonate minerals]]
[[Category:Sulfate minerals]]
[[Category:Phosphate minerals]]
[[Category:Silicate minerals]]
[[Category:Sodium minerals]]
[[Category:Aluminium minerals]]
[[Category:Copper minerals]]
[[Category:Iron minerals]]
[[Category:Magnesium minerals]]
[[Category:Mining terminology]]
[[Category:Mineral groups]]