Malachite

==Use==
[[File:Ajuar funerario de la Reina Roja - 8.jpg|thumb|left|The funerary mask of the [[Tomb of the Red Queen|Red Queen]] of [[Palenque]] is made from a mosaic of malachite.<ref>{{cite web |title=The Red Queen and Her Sisters: Women of Power in Golden Kingdoms|url=https://www.metmuseum.org/blogs/now-at-the-met/2018/golden-kingdoms-red-queen-women-of-power |website=www.metmuseum.org |access-date=13 October 2018}}</ref>]]

Malachite was used as a mineral pigment in green paints from antiquity until {{circa}} 1800.<ref>Gettens, R.J. and Fitzhugh, E. W. (1993) "Malachite and Green Verditer", pp. 183–202 in ''Artists’ Pigments. A Handbook of Their History and Characteristics'', Vol. 2: A. Roy (Ed.) Oxford University Press. {{ISBN|0894682601}}</ref> The pigment is moderately [[Lightfastness|lightfast]], sensitive to [[acid]]s, and varying in color. This natural form of green pigment has been replaced by its synthetic form, [[Basic_copper_carbonate|verditer]], among other synthetic greens.

Malachite is also used for decorative purposes, such as in wands and the [[Malachite Room of the Winter Palace|Malachite Room]] in the [[Hermitage Museum]],<ref>{{Cite journal|last=Budrina|first=Ludmila|title=Малахитовые залы Петербурга, России, Европы... / Malachite salon of St.-Petersburg, Russia, Europe...|url=https://www.academia.edu/7717944|journal=// Блистательный Петербург. Роль архитекторов ХIХ века в создании неповторимого облика города. Материалы научно-практической конференции. Кафедра. Сб. науч. Ст. – СПб.: Государственный музей-памятник «Исаакиевский собор», 2011. – С. 23-49.|date=January 2011|language=en}}</ref> which features a huge malachite vase, and the Malachite Room in [[Castillo de Chapultepec]] in [[Mexico City]].<ref>{{Cite journal|last=Budrina|first=Ludmila|title=La produzione in malachite dei Demidov: sulle trace degli oggetti alla prima esposizione universale / I Demidoff fra Russia e Italia. Gusto e prestigio di une famiglia in Europa dal XVIII al XX secolo. – P. 151-176, 9 tav.|url=https://www.academia.edu/7803720|journal=// I Demidoff Fra Russia e Italia. Gusto e Prestigio di Une Famiglia in Europa Dal XVIII al XX Secolo. A Cura di Lucia Tonini. Cultura e Memoria, Vol. 50. – Firenze: Leo S. Olschki, 2013.|date=January 2013|language=en}}</ref> Another example is the Demidov Vase, part of the former [[Demidov Collection|Demidov family collection]], and now in the [[Metropolitan Museum of Art]].<ref>[https://www.metmuseum.org/art/collection/search/199500 Monumental vase lapidary work: early 19th century; pedestal and mounts: 1819] Metropolitan Museum of Art. Retrieved 25 April 2021.</ref> "The [[Tazza (cup)|Tazza]]", a large malachite vase, one of the largest pieces of malachite in North America and a gift from [[Nicholas II of Russia|Tsar Nicholas II]], stands as the focal point in the centre of the room of [[Linda Hall Library]]. In the time of [[Nicholas I of Russia|Tsar Nicolas I]] decorative pieces with malachite were among the most popular diplomatic gifts.<ref>{{Cite book|last=Будрина|first=Людмила|title=Малахитовая дипломатия|publisher=Кабинетный ученый|year=2020|isbn=978-5-6044025-1-1|location=Екатеринбург|pages=208}}</ref> It was used in China as far back as the [[Eastern Zhou]] period.<ref>{{cite journal |last1=Langhals |first1=Heinz |last2=Bathelt |first2=Daniela |title=The Restoration of the Largest Archaelogical Discovery—a Chemical Problem: Conservation of the Polychromy of the Chinese Terracotta Army in Lintong |journal=Angewandte Chemie International Edition |date=1 December 2003 |volume=42 |issue=46 |pages=5676–5681 |doi=10.1002/anie.200301633|pmid=14661198}}</ref> The base of [[FIFA World Cup Trophy]] has two layers of malachite.

===Symbolism and superstitions===
A 17th-century Spanish superstition held that having a child wear a lozenge of malachite would help them sleep, and keep evil spirits at bay.<ref>The Illustrated Book of Signs and Symbols by Miranda Bruce-Mitford, Dorling Kindersley Limited, London, 1996, p. 41</ref> [[Marbodus]] recommended malachite as a talisman for young people because of its protective qualities and its ability to help with sleep.<ref name="Talismans p. 254">The Book of Talismans, Amulets and Zodiacal Gems, by William Thomas and Kate Pavitt, [1922], p. 254</ref> It has also historically been worn for protection from lightning and contagious diseases and for health, success, and constancy in the affections.<ref name="Talismans p. 254"/> During the Middle Ages it was customary to wear it engraved with a figure or symbol of the Sun to maintain health and to avert depression to which [[Capricorn (astrology)|Capricorns]] were considered vulnerable.<ref name="Talismans p. 254"/>

In [[ancient Egypt]] the colour green (wadj) was associated with death and the power of resurrection as well as new life and fertility. Ancient Egyptians believed that the [[afterlife]] contained an eternal paradise, referred to as the "Field of Malachite", which resembled their lives but with no pain or suffering.<ref>{{Cite web|url=http://www.ancientegyptonline.co.uk/colourgreen.html|title=Meaning of green in ancient Egypt|last=Hill|first=J|date=2010|website=Ancient Egypt Online|access-date=2016-11-28}}</ref>

===Ore uses===
[[File:Natural_copper_nugget.jpg|thumb|Copper nugget example]]
Simple methods of [[copper ore]] extraction from malachite involved thermodynamic processes such as [[smelting]].<ref name="Johnson-2004">{{Cite journal|last1=Johnson|first1=Cris E.|last2=Yee|first2=Gordon T.|last3=Eddleton|first3=Jeannine E.|date=2004-12-01|title=Copper Metal from Malachite circa 4000 B.C.E.|url=https://doi.org/10.1021/ed081p1777|journal=Journal of Chemical Education|volume=81|issue=12|pages=1777|doi=10.1021/ed081p1777|bibcode=2004JChEd..81.1777J|issn=0021-9584}}</ref> This reaction involves the addition of heat and a carbon, causing the carbonate to decompose leaving [[Copper(II) oxide|copper oxide]] and an additional carbon source such as coal converts the copper oxide into copper metal.<ref name="Johnson-2004"/><ref name="Day-2019">{{Citation|last1=Day|first1=Jo|title=Reconstructing a Bronze Age Kiln from Priniatikos Pyrgos, Crete|date=2019-09-30|url=http://dx.doi.org/10.2307/j.ctvpmw4g8.11|work=Experimental Archaeology: Making, Understanding, Story-telling|pages=63–72|publisher=Archaeopress Publishing Ltd|isbn=978-1-78969-320-1|access-date=2021-02-25|last2=Kobik|first2=Maggie|doi=10.2307/j.ctvpmw4g8.11|s2cid=210629355}}</ref>

The basic word equation for this reaction is:

Copper carbonate + heat → carbon dioxide + copper oxide (color changes from green to black).<ref name="Johnson-2004"/><ref name="Day-2019"/>

Copper oxide + carbon → carbon dioxide + copper (color change from black to copper colored).<ref name="Johnson-2004"/><ref name="Day-2019"/>

Malachite is a low grade copper ore, however, due to increase demand for metals, more economic processing such as [[Hydrometallurgy|hydrometallurgical]] methods (using aqueous solutions such as [[sulfuric acid]]) are being used as malachite is readily soluble in dilute acids.<ref>{{Cite journal|last1=Ata|first1=O. N.|last2=Yalap|first2=H.|date=2007-06-01|title=Optimization of Copper Leaching from Ore Containing Malachite|url=https://doi.org/10.1179/cmq.2007.46.2.107|journal=Canadian Metallurgical Quarterly|volume=46|issue=2|pages=107–114|doi=10.1179/cmq.2007.46.2.107|bibcode=2007CaMQ...46..107A |s2cid=98163205|issn=0008-4433}}</ref><ref>{{Cite web|title=Malachite|url=https://www.mindat.org/min-2550.html|access-date=2021-03-12|website=www.mindat.org}}</ref> [[Sulfuric acid]] is the most common leaching agent for copper oxide ores like malachite and eliminates the need for smelting processes.<ref name="Shabani-2012">{{Cite journal|last1=Shabani|first1=M. A.|last2=Irannajad|first2=M.|last3=Azadmehr|first3=A. R.|date=2012-09-01|title=Investigation on leaching of malachite by citric acid|url=https://doi.org/10.1007/s12613-012-0628-9|journal=International Journal of Minerals, Metallurgy, and Materials|language=en|volume=19|issue=9|pages=782–786|doi=10.1007/s12613-012-0628-9|bibcode=2012IJMMM..19..782S|s2cid=96128268|issn=1869-103X}}</ref>

The chemical equation for sulfuric acid leaching of copper ore from malachite is as follows:<ref name="Shabani-2012"/>

{{NumBlk|:
|{{overset|malachite|{{chem2|Cu2(OH)2CO3}}}} + {{overset|sulfuric acid|{{chem2|2H2SO4}}}} → {{overset|copper sulfate|{{chem2|2CuSO4}}}} + {{overset|carbon dioxide|{{chem2|CO2}}}} + {{overset|water|{{chem2|3H2O}}}}
|{{EquationRef|Reaction 1}}}}