Chemistry:Orichalcum
| Orichalcum | |
|---|---|
 A bronze sestertius coin from the time of Caligula | |
| Type | Metal |
Orichalcum or aurichalcum /ˌɔːrɪˈkælkəm/ is a metal mentioned in several ancient writings, including the story of Atlantis in the Critias of Plato. Within the dialogue, Critias (460–403 BC) says that orichalcum had been considered second only to gold in value and had been found and mined in many parts of Atlantis in ancient times, but that by Critias's own time, orichalcum was known only by name.[1]
Orichalcum may have been a noble metal such as platinum,[2] as it was supposed to be mined, but has been identified as pure copper or certain alloys of bronze, and especially brass alloys [3] in the case of antique roman coins, the latter being of "similar appearance to modern brass" according to scientific research.[4]
Overview
The name is derived from the Greek ὀρείχαλκος, oreikhalkos (from ὄρος, oros, mountain and χαλκός, chalkos, copper), literally meaning "mountain copper".
The Romans transliterated "orichalcum" as "aurichalcum", which was thought to mean literally "gold copper". It is known from the writings of Cicero that the metal which they called orichalcum resembled gold in color but had a much lower value.[5] In Virgil's Aeneid, the breastplate of Turnus is described as "stiff with gold and white orichalc".
Orichalcum has been vaguely identified by ancient Greek authors to be either a gold–copper alloy, a form of pure copper or even a copper ore and or various chemicals based on said metal, but also copper–tin and copper–zinc alloys, or even a metal or metallic alloy supposedly no longer known.
In later years, "orichalcum" was used to describe the sulfide mineral chalcopyrite and also to describe brass. These usages are difficult to reconcile with the claims of Plato's Critias, who states that the metal was "only a name" by his time,[1] while brass and chalcopyrite were very important in the time of Plato,[citation needed] as they still are today.
Joseph Needham notes that Bishop Richard Watson, an 18th century professor of chemistry, wrote of an ancient idea that there were "two sorts of brass or orichalcum". Needham also suggests that the Greeks may not have known how orichalcum was made and that they might even have had an imitation of the original.[6]
Ingots found
In 2015, 39 ingots thought by some to be orichalcum were discovered in a sunken vessel on the coast of Gela in Sicily which have tentatively been dated at 2,100 years old. They were analyzed with X-ray fluorescence and found to be an alloy consisting of 75–80% copper, 15–20% zinc, and smaller percentages of nickel, lead, and iron.[7] Another cache of 47 ingots were recovered in February 2016 and found to have similar composition as measured with ICP-OES and ICP-MS: around 65–80% copper, 15–25% zinc, 4–7% lead, 0.5–1% nickel, and trace amounts of silver, antimony, arsenic, bismuth and other elements.[8]
In ancient literature
Orichalcum is first mentioned in the 7th century BC by Hesiod, and in the Homeric hymn dedicated to Aphrodite, dated to the 630s.[citation needed]
According to the Critias of Plato, the inner wall surrounding the citadel of Atlantis with the Temple of Poseidon "flashed with the red light of orichalcum". The interior walls, pillars, and floors of the temple were completely covered in orichalcum, and the roof was variegated with gold, silver, and orichalcum. In the center of the temple stood a pillar of orichalcum, on which the laws of Poseidon and records of the first son princes of Poseidon were inscribed.[9]
Pliny the Elder points out that orichalcum had lost currency due to the mines being exhausted. Pseudo-Aristotle in De mirabilibus auscultationibus (62) describes a type of copper that is "very shiny and white, not because there is tin mixed with it, but because some earth is combined and molten with it." This might be a reference to orichalcum obtained during the smelting of copper with the addition of "cadmia", a kind of earth formerly found on the shores of the Black Sea, which is attributed to be zinc oxide.[10]
Numismatics
In numismatics, the term "orichalcum" is used to refer exclusively to a type of brass alloy used for minting Roman as, sestertius, dupondius and semis type of coins. It is considered more valuable than copper, of which the as coin was previously made.[11]
See also
- Ashtadhatu
- Auricupride
- Corinthian bronze
- Electrum
- Hepatizon
- Panchaloha
- Shakudō
- Shibuichi
- Thokcha
- Tumbaga
References
- ↑ 1.0 1.1 "The Internet Classics Archive | Critias by Plato". Paragraph 13. http://classics.mit.edu/Plato/critias.html.
- ↑ Cf. Felice Vinci, The Baltic Origins of Homer's Epic Tales. The "Illiad", the "Odyssey" and the Migration of Myth, Inner Traditions, Rochester (Vermont) 2005.
- ↑ Microstructure and chemical composition of Roman orichalcum coins emitted after the monetary reform of Augustus (23 B.C.); Volume 9, article number 12668 Published 03 September 2019 ; authors Melania Di Fazio, Anna Candida Felici, Fiorenzo Catalli & Caterina De Vito ; DOI: 10.1038/s41598-019-48941-4 ; open access article : https://link.springer.com/article/10.1038/s41598-019-48941-4 ; excerpt: The term Orichalcum is a classical ancient word used to describe a Cu-Zn-based alloy with a discrete percentage of Zn (5–28%), and similar in appearance to the modern brass
- ↑ Caley, Earle Radcliffe (1964). Orichalcum and Related Ancient Alloys: Origin, Composition, and Manufacture: With Special Reference to the Coinage of the Roman Empire, Issues 151-154 Front Cover. American Numismatic Society. pp. 2, 92, 105. https://books.google.com/books?id=BUVmAAAAMAAJ&q=Orichalcum.
- ↑ Polehampton, Edward (1815). The Gallery of Nature and Art; Or, a Tour Through Creation and Science. R. Wilks for C. Cradock & W. Joy. p. 272. https://archive.org/details/gallerynaturean08polegoog. "Whether, if a person should offer a piece of gold to sale, thinking that he was only disposing of a piece of orichalcum, an honest man ought to inform him that it was really gold, or might fairly buy for a penny what was worth a thousand times as much"
- ↑ Needham, Joseph (1974). Science and Civilisation in China. 5,Chemistry and Chemical Technology; Part 2, Spagyrical Discovery and Invention: Magisteries of Gold and Immortality. Cambridge University Press. pp. 227–228. ISBN 978-0521085717.
- ↑ Saraceni, Jessica E.. "Unusual Metal Recovered from Ancient Greek Shipwreck". http://www.archaeology.org/news/2874-150107-sicily-orichalcum-metal.
- ↑ Caponetti, Eugenio; Armetta, Francesco; Brusca, Lorenzo; Ferrante, Marco; Martino, Delia Chillura; Saladino, Maria Luisa; Guastella, Dario; Chirco, Gabriella et al. (June 2021). "Newly discovered orichalcum ingots from Mediterranean sea: Further investigation". Journal of Archaeological Science: Reports 37 (102901): 102901. doi:10.1016/j.jasrep.2021.102901. Bibcode: 2021JArSR..37j2901C.
- ↑ "The Internet Classics Archive | Critias by Plato". Paragraphs 14-15. http://classics.mit.edu/Plato/critias.html.
- ↑ Zhirov, Nicholas F. (2001). Atlantis: Atlantology: Basic Problems. The Minerva Group, Inc.. p. 46. ISBN 0-89875-591-3. https://books.google.com/books?id=hKVQFP47tJQC&q=Orichalcum.
- ↑ Microstructure and chemical composition of Roman orichalcum coins emitted after the monetary reform of Augustus (23 B.C.); Volume 9, article number 12668 Published 03 September 2019 ; authors Melania Di Fazio, Anna Candida Felici, Fiorenzo Catalli & Caterina De Vito ; DOI: 10.1038/s41598-019-48941-4 ; open access article : https://link.springer.com/article/10.1038/s41598-019-48941-4 ; excerpts: The term Orichalcum is a classical ancient word used to describe a Cu-Zn-based alloy with a discrete percentage of Zn (5–28%), and similar in appearance to the modern brass [...] These coins, consisting of asses, sestertii, dupondii and semisses, were analysed using non- and invasive analyses, aiming to explore microstructure, corrosive process and to acquire quantitative chemical analysis [...] Orichalcum was rarely used for coinage in the Hellenistic world and was experimentally used by Romans under the reigns of Caesar and Marcus Antonius.
External links
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