Realgar
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| Realgar | |
|---|---|
| Lua error in package.lua at line 80: module 'Module:InfoboxImage/data' not found. Realgar crystals, Royal Reward Mine, King County, Washington, US | |
| General | |
| Category | Sulfide mineral |
| Formula | Page Module:Chem2/styles.css has no content.As4S4 or AsS |
| IMA symbol | Rlg[1] |
| Strunz classification | 2.FA.15a |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
| Space group | P21/n (no. 14) |
| Unit cell | a = 9.325(3) Å b = 13.571(5) Å c = 6.587(3) Å β = 106.43°; Z = 16 |
| Identification | |
| Color | Red to yellow-orange; in polished section, pale gray, with abundant yellow to red internal reflections |
| Crystal habit | Prismatic striated crystals; more commonly massive, coarse to fine granular, or as incrustations |
| Twinning | Contact twins on {100} |
| Cleavage | Good on {010}; less so on {101}, {100}, {120}, and {110} |
| Tenacity | Sectile, slightly brittle |
| Mohs scale hardness | 1.5–2 |
| Luster | Resinous to greasy |
| Streak | Red-orange to red |
| Diaphaneity | Transparent |
| Specific gravity | 3.56 |
| Optical properties | Biaxial (−) |
| Refractive index | nα = 2.538 nβ = 2.684 nγ = 2.704 |
| Birefringence | δ = 0.166 |
| Pleochroism | Nearly colorless to pale golden yellow |
| 2V angle | 40° |
| Dispersion | r > v, very strong |
| Other characteristics | Toxic and carcinogenic. Disintegrates on long exposure to light to a powder composed of pararealgar or arsenolite and orpiment. |
| References | [2][3][4][5][6] |
Realgar (/riˈælɡɑːr, -ɡər/ Script error: No such module "Respell".), also known as arsenic blende, ruby sulphur or ruby of arsenic, is an arsenic sulfide mineral with the chemical formula Page Module:Chem2/styles.css has no content.α-As4S4. It is a soft mineral occurring in monoclinic crystals, or in granular, compact, or powdery form, often in association with the related mineral, orpiment (Page Module:Chem2/styles.css has no content.As2S3). It is orange-red in color, and burns with a bluish flame releasing fumes of arsenic and sulfur. It is trimorphous with pararealgar and bonazziite.[2]
Etymology
Its name comes from the Arabic rahj al-ġār (Script error: No such module "Lang". Script error: No such module "IPA". <phonos file="Q109746-ar.ogg">listen</phonos>, "powder of the mine"), via Medieval Latin, and its earliest record in English is in the 1390s.[7][8][9]
Uses
Realgar is a minor ore of arsenic extracted in China, Peru, and the Philippines.[10]
Historical uses
Realgar was used by firework manufacturers in white flame and star compositions and to produce yellow smoke in daytime fireworks.[11][12]
Realgar has been used to kill weeds, insects, and rodents,[13] even though more effective arsenic-based anti-pest agents are available such as cacodylic acid, Page Module:Chem2/styles.css has no content.(CH3)2As(O)OH, an organoarsenic compound used as an herbicide.[citation needed]
Realgar was also used by Ancient Greek apothecaries to make a medicine known as "bull's blood".[14] The Greek physician Nicander described a death by "bull's blood", which matches the known effects of arsenic poisoning.[14] Bull's blood is the poison that is said to have been used by Themistocles and Midas for suicide.[14]
The Chinese name for realgar is Script error: No such module "Lang". (Mandarin Script error: No such module "lang".), literally 'masculine yellow', as opposed to orpiment which is 'feminine yellow'.[15]
Realgar was, along with orpiment, traded in the Roman Empire and was used as a red paint pigment. Early occurrences of realgar as a red paint pigment are known for works of art from China, India, Central Asia, and Egypt. It was used in Venetian fine-art painting during the Renaissance era, though rarely elsewhere in Europe, a use which died out by the 18th century.[16] It was also used as medicine. Other traditional uses include manufacturing lead shot, printing, and dyeing[how?] calico cloth. It was used to poison rats in medieval Spain and in 16th century England.[17]
Occurrence
Realgar most commonly occurs as a low-temperature hydrothermal vein mineral associated with other arsenic and antimony minerals. It also occurs as volcanic sublimations and in hot spring deposits. It occurs in association with orpiment, arsenolite, calcite and barite.[2]
It is found with lead, silver and gold ores in Hungary, Bohemia and Saxony. In the US it occurs notably in Mercur, Utah; Manhattan, Nevada; and in the geyser deposits of Yellowstone National Park.[5]
After a long period of exposure to light, realgar changes form to a yellow powder known as pararealgar (Page Module:Chem2/styles.css has no content.β-As4S4). It was once thought that this powder was the yellow sulfide (orpiment), but is a distinct chemical compound.[18]
Gallery
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The unit cell of realgar, showing clearly the Page Module:Chem2/styles.css has no content.As4S4 molecules it contains
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Cluster of realgar crystals from Getchell Mine, Adam Peak, Potosi District, Humboldt County, Nevada, United States
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Cherry-red realgar crystals atop a matrix, and a sharp acicular spray of the rare species picropharmacolite (white needles) below
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Crystals of realgar, quartz, chalcopyrite and galena, from Quiruvilca Mine, La Libertad, Peru
See also
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- Classification of minerals
- List of inorganic pigments
- List of minerals
- Realgar wine or Xionghuang wine is a Chinese alcoholic drink that is made from Chinese liquor dosed with powdered realgar.[19]
References
Page Template:Reflist/styles.css has no content.
- ^ Page Module:Citation/CS1/styles.css has no content.Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ a b c Page Module:Citation/CS1/styles.css has no content."Realgar" (PDF). Handbook of Mineralogy. RRUFF Project.
- ^ Page Module:Citation/CS1/styles.css has no content."Realgar". mindat.org.
- ^ Page Module:Citation/CS1/styles.css has no content.Realgar, WebMineral.com
- ^ a b Page Module:Citation/CS1/styles.css has no content.Klein, Cornelis; Hurlbut, Cornelius S. (1985). Manual of Mineralogy (20th ed.). Wiley. p. 282. ISBN 0-471-80580-7.
- ^ Page Module:Citation/CS1/styles.css has no content.Hejny, Clivia; Sagl, Raffaela; Többens, Daniel M.; Miletich, Ronald; Wildner, Manfred; Nasdala, Lutz; Ullrich, Angela; Balic-Zunic, Tonci (May 2012). "Crystal-structure properties and the molecular nature of hydrostatically compressed realgar". Physics and Chemistry of Minerals. 39 (5): 399–412. Bibcode:2012PCM....39..399H. doi:10.1007/s00269-012-0495-y. S2CID 96885484.
- ^ Page Module:Citation/CS1/styles.css has no content.Philip Babcock Grove, ed. (1993). Webster's Third New International Dictionary. Merriam-Webster, inc. ISBN 3-8290-5292-8.
- ^ Page Module:Citation/CS1/styles.css has no content."Bonazziite".
- ^ Page Module:Citation/CS1/styles.css has no content."List of Minerals". 21 March 2011.
- ^ Page Module:Citation/CS1/styles.css has no content."Arsenic" (PDF). Mineral commodity summaries. United States Geological Survey. January 2021. Retrieved 28 February 2021.
- ^ Page Module:Citation/CS1/styles.css has no content.Weingart, George Washington (1947). "I". Pyrotechnics (2nd: Revised, Enlarged, and Corrected ed.). USA: G.W. Weingart. p. 9. Retrieved 26 September 2025.
Red Arsenic... They are very useful in making white stars, especially as they take fire far more easily than those made from antimony.
- ^ Page Module:Citation/CS1/styles.css has no content.Izzo, Colonello Dott. Attilio (1950). "5-1: Ricettario di Composizioni Pirotecniche". In Hoepli, Ulrico (ed.). Pirotecnia e Fuochi Artificiali [Pyrotechnics and Fireworks] (PDF) (in italiano). Milano: A. Izzo. pp. 216, 218.
- ^ Page Module:Citation/CS1/styles.css has no content.Realgar (PDF). N.J. Department of Environmental Protection (Report). Hazardous Substance Factsheet. State of New Jersey. April 2008.
- ^ a b c Page Module:Citation/CS1/styles.css has no content.Arnould, Dominique (1993). "Boire le sang de taureau: La mort de Thémistocle" [Drinking bull's blood: The death of Themistocles]. Revue de philologie, de littérature et d'histoire anciennes (in français). LXVII (2): 229–235.
- ^ Page Module:Citation/CS1/styles.css has no content.Jie Liu; Yuanfu Lu; Qin Wu; Robert A. Goyer; Michael P. Waalkes (August 2008). "Mineral arsenicals in traditional medicines: Orpiment, realgar, and arsenolite" (PDF). Journal of Pharmacology and Experimental Therapeutics. 326 (2): 363–368. doi:10.1124/jpet.108.139543. PMC 2693900. PMID 18463319. Archived from the original (PDF) on 2022-07-06. Retrieved 2021-06-05.
- ^ Page Module:Citation/CS1/styles.css has no content."Realgar". Boston, MA: Museum of Fine Arts.
- ^ Page Module:Citation/CS1/styles.css has no content.Henri Lammens S.J. (1890). Remarques sur les mots français dérivés de l'arabe [Notes on French words derived from Arabic] (in français). Beyrouth Impr. Catholique – via archive.org.
- ^ Page Module:Citation/CS1/styles.css has no content.Douglass, D. L.; Shing, Chichang; Wang, Ge (1992). "The light-induced alteration of realgar to pararealgar" (PDF). American Mineralogist. 77: 1266–1274. Retrieved 11 August 2014.
- ^ Page Module:Citation/CS1/styles.css has no content."Dragon Boat Festival activities expanded". www.chinadaily.com.cn. Retrieved 11 March 2023.
Further reading
- Page Module:Citation/CS1/styles.css has no content.Craigie, W.A.; Bradley, H. (1914). "Realgar". In Sir James, A.H. Murray (ed.). A New English Dictionary on Historical Principles. Clarendon Press at Oxford. p. 202 – via archive.org.
- Page Module:Citation/CS1/styles.css has no content.William Mesny (1899). Mesny's Chinese Miscellany. A Text Book of Notes on China and the Chinese. Vol. III. Shanghai. p. 251.
- Page Module:Citation/CS1/styles.css has no content.William Mesny (1905). Mesny's Chinese Miscellany. A Text Book of Notes on China and the Chinese. Vol. IV. Shanghai. pp. 425–426.
External links
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