Variscite

{{short description|Hydrated aluminium phosphate}} {{Infobox mineral | name = Variscite | category = Phosphate minerals | boxwidth = | boxbgcolor = #36c08f | image = Variscite-Pyrite-179447.jpg | imagesize = 260px | caption = | formula = AlPO4·2H2O | IMAsymbol = Var<ref>{{cite magazine |last=Warr|first=L. N. |date=2021 |title=IMA–CNMNC approved mineral symbols |magazine=Mineralogical Magazine |volume=85 |issue=3 |pages=291–320 |publisher=Mineralogical Society of Great Britain and Ireland |doi=10.1180/mgm.2021.43 |bibcode=2021MinM...85..291W |s2cid=235729616 |doi-access=free}}</ref> | molweight = | strunz = 8.CD.10 | color = Pale to emerald-green (pale green in transmitted light), green, blue green, yellow green, pale shades of brown or yellow, rarely red and colourless to white | habit = Encrustations and reniform masses | system = Orthorhombic | class = Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) | symmetry = ''Pbca'' | twinning = | cleavage = [010] perfect | fracture = Conchoidal to splintery | mohs = 4.5 | luster = Vitreous to waxy | refractive = nα = 1.563 nβ = 1.588 nγ = 1.594 | opticalprop = Biaxial (−) | birefringence = δ = 0.031 | pleochroism = | streak = White | gravity = 2.57 to 2.61 | density = | melt = | fusibility = | diagnostic = | solubility = | diaphaneity = Transparent to translucent | other = | references =<ref name=HoM>{{cite web |url=https://rruff.info/doclib/hom/variscite.pdf |title=Variscite |website=Handbook of Mineralogy |publisher=RRUFF Project}}</ref><ref name=mindat>{{Mindat |id=4156 |name=Variscite}}</ref><ref name=webmin>{{WebMineral |url=https://webmineral.com/data/Variscite.shtml |title=Variscite Mineral Data}}</ref> }} '''Variscite''' is a relatively rare hydrated aluminium phosphate mineral ({{chem2|AlPO4*2H2O}}). It is sometimes confused with turquoise; however, variscite is usually greener in color. The green color results from the presence of small amounts of trivalent chromium ({{chem|Cr|3+}}).<ref name="gemselect"/>

==Geology== Variscite is a secondary mineral formed by direct deposition from phosphate-bearing water which has reacted with aluminium-rich rocks in a near-surface environment.<ref>{{cite journal|last1=Roncal-Herrero|first1=T.|last2=Rodríguez-Blanco|first2=J. D.|last3=Benning|first3=L. G.|last4=Oelkers|first4=E. H.|title=Precipitation of Iron and Aluminum Phosphates Directly from Aqueous Solution as a Function of Temperature from 50 to 200 °C|journal=Crystal Growth & Design|date=2009|volume=9|issue=12|pages=5197–5205|doi=10.1021/cg900654m}}</ref> It occurs as fine-grained masses in nodules, cavity fillings, and crusts. Variscite often contains white veins of the calcium aluminium phosphate mineral crandallite.

It was first described in 1837 and named for the locality of Variscia, the historical name of the Vogtland, in Germany. At one time, variscite was called ''Utahlite''. At times, materials which may be turquoise or may be variscite have been marketed as "variquoise". Appreciation of the color ranges typically found in variscite have made it a popular gem in recent years.<ref name="nevadaminerals">Minerals of Nevada – Nevada Bureau of Mines Special Pub. 31 University of Nevada Press, 2004 Pages 78–81</ref>

Variscite from Nevada typically contains black spiderwebbing in the matrix and is often confused with green turquoise. Most of the Nevada variscite recovered in recent decades has come from mines located in Lander County<ref>Gemstones of North America Volume III by John Sinkankas – Geoscience Press 1997</ref> and Esmeralda County, specifically in the Candelaria Hills.

Notable localities are Lucin, Snowville, and Fairfield in Utah, United States. Most recently found in Wyoming as well. It is also found in Germany, Australia, Poland, Spain,<ref>{{cite web|url=http://www.patrimonigava.cat/lahistoriajaciment|title=www.patrimonigava.cat|website=www.patrimonigava.cat|access-date=2015-08-31|archive-date=2018-09-03|archive-url=https://web.archive.org/web/20180903083945/http://www.patrimonigava.cat/lahistoriajaciment|url-status=dead}}</ref> Italy (Sardinia), Brazil, and Iran (Yazd).

==Jewelry== Variscite has been used in Europe to make personal ornaments, especially beads, since Neolithic times. In the tumulus (burial mounds) excavated in the 19th century in Brittany (France)—among them the tomb of Mané er Hroëck in Locmariaquer and the Tumiac mound in Arzon—dating from the Neolithic period, between 4500 and 4000 BCE, many ornamental pieces, beads, and pendants were found. These were made from a green stone that Alexis Damour identified as a hydrated aluminum phosphate containing some iron, which he considered equivalent to the ''callaïs'' described by Pliny in his ''Natural History''. Later, variscite was found in Neolithic archaeological sites in Spain as well.<ref>{{Cite book |last=Muñoz Amilibia |first=Ana María |title=La cultura neolítica catalana de los “sepulcros de fosa” |publisher=Universidad de Barcelona |year=1965 |location=Barcelona, Spain |pages=248–260 |language=es |trans-title=The Catalan Neolithic culture of the “pit graves.”}}</ref> During Roman times, variscite was used to imitate emerald crystals employed as pendants, being carved into prisms drilled longitudinally through the center but having eight faces instead of the six typical of emerald crystals.<ref>{{Cite book |last=Calvo Rebollar |first=Miguel |title=Gemas de España. Tesoros de nuestra tierra. |publisher=Prames |year=2025 |isbn=978-42-8321-639-2 |location=Zaragoza, Spain |pages=57–62 |language=es |trans-title=Gems of Spain. Treasures of Our Land}}</ref> It was not until the 19th century that it was determined that all variscite used in Europe came from three sites in Spain, Gavá (Barcelona), Palazuelo de las Cuevas (Zamora), and Encinasola (Huelva).<ref>{{Cite book |last=Calvo Rebollar |first=Miguel |title=Minerales y Minas de España. Vol. VII. Fosfatos, Arseniatos y Vanadatos. |publisher=Escuela Técnica Superior de Ingenieros de Minas de Madrid. Fundación Gómez Pardo |year=2015 |location=Madrid |pages=260–276 |language=es}}</ref>

Variscite is sometimes used as a semi-precious stone, and is popular for carvings and ornamental use due to its beautiful and intense green color, and is commonly used in silversmithing in place of turquoise. Variscite is less common than turquoise. However, because it is not as commonly available or as well known to the general public, raw variscite tends to be less expensive than turquoise.<ref name="nevadaminerals" /><ref name="gemselect">{{cite web|url=https://www.gemselect.com/gem-info/variscite/variscite-info.php|title=Variscite Gemstone Information}}</ref><ref>{{cite web|url=https://www.gemsociety.org/article/variscite-jewelry-and-gemstone-information/|title=Variscite Value, Price, and Jewelry Information – International Gem Society}}</ref>

==Gallery== <gallery> Variscite Smithsonian.jpg|Cut slab of variscite at the Smithsonian. Specimen is roughly 0.5 m wide. 00021 11 cm variscite.jpg|Variscite filling the cracks in siltstone. The sample is from Queensland, Australia. The width of the view is {{convert|11|cm|abbr=on}}. Varis mcguin damali.jpg|Polished variscite from Nevada Variscite-bolo.jpg|Variscite and silver bolo tie. This variscite specimen contains inclusions of white crandallite and is from Clay Canyon near Fairfield, Utah. Callais Neolithique Musée Vannes 19082012 04.jpg|Necklace of variscite, from Neolithic tumulus of Turmiac c 4500-4000 BCE </gallery>

==See also== * {{Annotated link|Variscan orogeny}} (same etymology, as named from the ancient locality of Variscia in Germany) * List of minerals

==References== {{commons category| Variscite}}  {{reflist}}

Category:Aluminium minerals Category:Phosphate minerals Category:Orthorhombic minerals Category:Minerals in space group 61 Category:Luminescent minerals Category:Gemstones Category:Dihydrate minerals Category:Minerals described in 1837