Prasiolite

Not to be confused with Praseolite.

Prasiolite
General
CategoryTectosilicates, quartz variety
Crystal systemTrigonal
Identification
ColorShades of green
Crystal habitHexagonal prisms
CleavageNone
FractureConchoidal[1]
TenacityBrittle[1]
Mohs scale hardness7 – lower in impure varieties[1]
DiaphaneityTransparent to nearly opaque
Specific gravity2.65
Refractive index1.544 to 1.553[2]
Birefringence0.009[3]
Ultraviolet fluorescenceNone

Prasiolite (also known as green quartz, green amethyst or vermarine) is a green variety of quartz, with its color typically coming from Fe2+ ions within the crystal structure.[1][4]

Natural prasiolite is exceedingly rare, having been first discovered in the early 19th century in Lower Silesia, Poland[5][6] with only a few other deposits known to exist. Natural prasiolite deposits include Płóczki Górne (Poland), Bahia (Brazil), Thunder Bay (Canada), and Farm Rooisand (Namibia).[6]

Nearly all commercially available prasiolite is artificial, either produced by heat-treating amethysts from certain locations[7] to 400-500°C,[8] or irradiating yellow-tinged quartzes.[9] Most amethyst will turn yellow or orange when heated, producing heat-treated amethysts which are often marketed as citrine, but some amethyst will turn green when treated.[8] Significant prasiolite production began in the mid-1950s with the discovery that amethysts from the Montezuma mine in Minas Gerais, Brazil turned green when heat-treated.[10]

Most prasiolite sold is used in jewellery settings, where it can substitute for far more expensive gemstones, such as peridot, tsavorite, and emerald.[11] Prasiolite used for jewelry comes from two main sources: heat-treated amethyst from the Montezuma mine, and irradiated yellow-tinged quartz from various locations throughout Brazil.[4]

Green quartz is sometimes incorrectly called green amethyst,[12] which is not an acceptable name for the material according to Federal Trade Commission Guidelines.[13] Other names for green quartz include vermarine and lime citrine.[14]

The word prasiolite literally means "leek-green stone" and is derived from Ancient Greek πράσον prason meaning "leek" and λίθος lithos meaning "stone".[15][16] The stone was given its name due to its green-colored appearance.

Natural prasiolite is a very light, translucent green. Darker green quartz is generally the result of artificial treatment,[17] with lighter-colored prasiolite often irradiated with gamma rays as an attempt to obtain deeper colors.[18]

See also

References

  1. ^ a b c d "Prasiolite gemstone information". www.gemdat.org. Retrieved 19 April 2018.
  2. ^ Lazarelli. Blue Chart Gem Identification. p. 7.
  3. ^ "PRASIOLITE the green variety of quartz (aka Green Amethyst)". www.galleries.com. Retrieved 19 April 2018.
  4. ^ a b Praszkier, Tomasz; Kenis, Piotr; Komza, Piotr. "Prasiolite from Sokołowiec area, Kaczawskie Mountains, Lower Silesia, Poland". www.spiriferminerals.com. Retrieved 2 August 2025.
  5. ^ Czaja, Maria; Kądziołka-Gaweł, Mariola; Konefał, Adam; Sitko, Rafał; Teper, Ewa; Mazurak, Zbigniew; Sachanbiński, Michał (2017). "The Mössbauer spectra of prasiolite and amethyst crystals from Poland". Physics and Chemistry of Minerals. 44: 1. doi:10.1007/s00269-016-0864-z. ISSN 1432-2021.
  6. ^ a b Platonov, Alexej N.; Szuszkiewicz, Adam (2015). "Green to blue-green quartz from Rakowice Wielkie (Sudetes, south-western Poland) – a re-examination of prasiolite-related colour varieties of quartz". Mineralogia. 46 (1/2): 19–20. doi:10.1515/mipo-2016-0004.
  7. ^ Akhavan, Amir C. (2011). "Prasiolite". www.quartzpage.de. Retrieved 2 August 2025.
  8. ^ a b Henn, Ulrich; Schultz-Güttler, Rainer (2012). "Review of some current coloured quartz varieties" (PDF). The Journal of Gemmology. 33 (1–4): 34. doi:10.15506/JoG.2012.33.1.29. ISSN 1355-4565.
  9. ^ "Prasiolite". www.edelsteine.at. Retrieved 2 August 2025.
  10. ^ Fryer, C. W. (1996). "QUARTZ, Single-Crystal Green" (PDF). Gems & Gemology. 32 (3). Gemological Institute of America: 210–211. ISSN 0016-626X.
  11. ^ Sedawie, Ross (2025) [First Published 2022]. "Prasiolite Gemstone: Properties, Meanings, Value & More". www.gemrockauctions.com. Retrieved 2 August 2025.
  12. ^ "Green Amethyst". GemSelect. Retrieved 10 December 2012.
  13. ^ 16 CFR 23.26
  14. ^ "Green Quartz Meaning and Properties". firemountaingems.com. n.d. Retrieved 21 October 2021.
  15. ^ Bailey, Dorothy; Bailey, Kenneth C. (1929). An Etymological Dictionary of Chemistry and Mineralogy. E. Arnold & Company. p. 222.
  16. ^ "Prasiolite". www.langantiques.com. Retrieved 2 August 2025.
  17. ^ Gems and Gemstones: Timeless Natural Beauty of the Mineral World By Lance Grande, Allison Augustyn, p.91
  18. ^ Nunes, Eduardo H.M.; Lameiras, Fernando S.; Houmard, Manuel; Vasconcelos, Wander L. (2013). "Spectroscopic study of natural quartz samples". Radiation Physics and Chemistry. 90: 80. doi:10.1016/j.radphyschem.2013.05.003. ISSN 1879-0895.


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