Its name is taken from that of theAmazon River, from which green stones were formerly obtained, though it is unknown whether those stones were amazonite.[4] Although it has been used for jewellery for well over three thousand years, as attested by archaeological finds in Middle and New Kingdom Egypt[8] and Mesopotamia, no ancient or medieval authority mentions it. It was first described as a distinct mineral only in the 18th century.[9]
Green and greenish-blue varieties of potassium feldspars that are predominantly triclinic are designated as amazonite.[10] It has been described as a "beautiful crystallized variety of a bright verdigris-green"[11] and as possessing a "lively green colour".[4] It is occasionally cut and used as agemstone.[12]
Amazonite is a mineral of limited occurrence. In Bronze Age Egypt, it was mined in the southern Eastern Desert at Gebel Migif. In early modern times, it was obtained almost exclusively from the area ofMiass in theIlmensky Mountains, 50 miles (80 km) southwest ofChelyabinsk,Russia, where it occurs ingranitic rocks.[4]
Amazonite is now known to occur in various places around the world. Those places are, among others, as follows:
For many years, the source of amazonite's color was a mystery.[20] Some people assumed the color was due to copper becausecopper compounds often have blue and green colors.[20] A 1985 study suggests that the blue-green color results from quantities oflead and water in the feldspar.[20] Subsequent 1998 theoretical studies by A. Julg expand on the potential role of aliovalent lead in the color of microcline.[21]
Other studies suggest the colors are associated with the increasing content of lead,rubidium, andthallium ranging in amounts between 0.00X and 0.0X in the feldspars, with even extremely high contents of PbO,lead monoxide, (1% or more) known from the literature.[10] A 2010 study also implicated the role of divalentiron in the green coloration.[7] These studies and associated hypotheses indicate the complex nature of the color in amazonite; in other words, the color may be the aggregate effect of several mutually inclusive and necessary factors.[9]
A 2021 study by the German Institut für Edelsteinprüfung (EPI) found that the amount of lead ions that leaked from an 11 g (0.39 oz) sample of amazonite into an acidic solution simulating saliva exceededEuropean Union standard DIN EN 71-3:2013's recommended amount by five times. This experiment was to simulate a child swallowing amazonite, and could also apply to "energy medicine" practices such as inserting the mineral into drinking water bottles.[22]
Large deep-turquoise amazonite crystal with attached stark-white microcline, fromKonso,SNNPR, Ethiopia. Size: 16.4 cm × 11.9 cm × 8.0 cm (6.5 in × 4.7 in × 3.1 in).
Twosmoky quartz crystals surrounded by amazonite crystals, from Smoky Hawk Mine, Crystal Peak,Teller County, Colorado. Size: 11.0 cm × 8.2 cm × 6.3 cm (4.3 in × 3.2 in × 2.5 in).
Deep lustrous crystal of amazonite, from Take 5 Claim, Crystal Peak,Teller County, Colorado. Size: 4.4 cm × 4.0 cm × 3.5 cm (1.7 in × 1.6 in × 1.4 in).
^abMikhail Ostrooumov,Amazonite: Mineralogy, Crystal Chemistry, and Typomorphism (Elsevier, 2016), p. 1–12.
^abcPivec, E.; Ševčik, J.; Ulrych, J. (December 1981). "Amazonite from the alkali granite of the Avdar Massif, Mongolia".TMPM Tschermaks Petr. Mitt.28 (4):277–283.Bibcode:1981TMPM...28..277P.doi:10.1007/BF01081855.
^"Common Minerals of Virginia".Virginia Department of Mines, Minerals and Energy. Commonwealth of Virginia. Archived fromthe original on 24 July 2021. Retrieved5 July 2019.
^Sihai, Liu; Changzhi, Wu; Lianxing, Gu; Zunzhong, Zhang; Junhua, Tang; Guangrong, Li; Ruxiong, Lei; Chuansheng, Wang (2008)."中天山白石头泉岩体年代学、岩石成因及构造意义" [Geochronology, petrogenesis and tectonic significances of the Baishitouquan pluton in Middle Tianshan, Northwest China].Acta Petrologica Sinica (in Chinese).24 (11). Beijing: China Science Publishing & Media Ltd.: 2720.ISSN1000-0569.
^Suayah, Ismail B.; Miller, Jonathan S.; Miller, Brent V.; et al. (April 2006). "Tectonic significance of Late Neoproterozoic granites from the Tibesti massif in southern Libya inferred from Sr and Nd isotopes and U–Pb zircon data".Journal of African Earth Sciences.44 (4–5): 564.Bibcode:2006JAfES..44..561S.doi:10.1016/j.jafrearsci.2005.11.020.ISSN1464-343X.S2CID26947582.
^Lundegårdh, Per H. (1971).Nyttosten i Sverige (in Swedish). Stockholm:Almqvist & Wiksell. p. 21.
^abPenick, D. Allen Jr.; Sweet, Palmer C. (May 1992)."Mineral collecting sites in Virginia"(PDF).Virginia Minerals.38 (2). Charlottesville, Virginia: Virginia Department of Mines, Minerals, and Energy:10–12. Archived fromthe original(PDF) on 24 April 2012.
Radioactive 14.05% (K)
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One or more of the preceding sentences incorporates text from a publication now in thepublic domain: Chisholm, Hugh, ed. (1911). "Amazon-stone".Encyclopædia Britannica. Vol. 1 (11th ed.). Cambridge University Press. p. 791.
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