Charoite

Properties

Charoite is translucent lavender to purple in color with a pearly luster. Charoite is strictly massive in nature, and fractures are conchoidal. It has an unusual swirling, fibrous appearance, sometimes chatoyant, and that, along with its intense color, can lead many to believe at first that it is synthetic or enhanced artificially. Though reportedly discovered in the 1940s, it was not known to most of the world until its description in 1978. It is said to be opaque and unattractive when found in the field; a fact that may have contributed to its late recognition. Charoite consists of oxygen (43.75%), silicon (27.65%) and calcium (17.53%) mainly, but its composition includes potassium (10.69%) - which gives it its radioactive properties - and hydrogen (0.39%) as well. It has a barely detectable, 0.65% radioactivity concentration per Gamma Ray American Petroleum Institute Units.

Inclusions mainly come in the swirly patterns of the mineral. The black spots on some specimens are either augite or aegirine, the latter occurring in almost all charoites since they commonly grow together. Larger round greenish spots are feldspar. Lighter colored stones or ones with translucent areas are likely due to canasite. The yellowish brown spots are tinaksite, which was discovered at the same time as charoite was. Charoite's silky, fibrous structure results in a shimmery looking polished stone. Sometimes, the very white flashes are tiny white feldspar. Sugilites and charoites can be confused, as both are purple, and sugilite can have black and white inclusions, however sugilite lacks the swirling pattern that are present in charoite stones, and it also lacks the chatoyant effect.

Occurrences

It has been reported only from the Aldan Shield, Sakha Republic, Siberia, Russia. It is found where a syenite of the Murun Massif has intruded into and altered limestone deposits producing a potassium feldspar metasomatite,

Gallery

Charoitite, sw Yakutia Siberia.jpg|Charoitite, a charoite-dominated potassic metasomatite rock from the type area. Photo is 5.7 cm wide. 2000 Charoite 613.jpg|Charoite postage stamp, 2000, from a series commemorating "300 Years of Mining and Geological Service in Russia."

References

References

1. Warr, L.N.. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine.
2. [https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Charoite Mineralienatlas]
3. "Charoite".
4. (2005). "Charoite". Mineral Data Publishing.
5. Ian Frazier, ''Travels in Siberia'', Farrar, Straus and Giroux, New York (NY), 2010, ISBN 978-0-374-27872-4, [https://books.google.com/books?id=Qc8UsH-rAL0C&pg=PA394 page 394]
6. (2014). "Charoite Mineral Data".
7. "Charoite Meaning, History and Detailed Information with Photos".
8. "What is Charoite? – A Complete Buying Guide {{!}} Jewelry Guide".
9. "Charoite Value, Price, and Jewelry Information".