CategoryOxide mineral
Crystal systemTrigonal
ColorShades of green
Crystal habitHexagonal prisms
Mohs scale hardness7 – lower in impure varieties[1]
DiaphaneityTransparent to nearly opaque
Specific gravity2.65
Refractive index1.544 to 1.553[2]
Ultraviolet fluorescenceNone

Prasiolite (also known as green quartz, green amethyst or vermarine) is a green variety of quartz.

Since 1950, almost all natural prasiolite has come from a small Brazilian mine, but it has also been mined in the Lower Silesia region of Poland. Naturally occurring prasiolite has also been found in the Thunder Bay area of Canada.[4]

Most prasiolite sold is used in jewellery settings, where it can substitute for far more expensive precious gemstones.

Prasiolite is a rare stone in nature; artificial prasiolite is produced by heat treatment of amethyst.[4] 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. Currently, almost all prasiolite on the market results from a combination of heat treatment and ionizing radiation.[5]

Green quartz is sometimes incorrectly called green amethyst,[6] which is not an acceptable name for the material according to Federal Trade Commission Guidelines. Other names for green quartz include vermarine and lime citrine.[7]

The word prasiolite literally means "scallion green-colored stone" and is derived from Greek πράσον prason meaning "leek" and λίθος lithos meaning "stone". The mineral 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.[8]

See also


  1. ^ a b c "Prasiolite gemstone information". Retrieved 19 April 2018.
  2. ^ Lazarelli. Blue Chart Gem Identification. p. 7.
  3. ^ "PRASIOLITE the green variety of quartz (aka Green Amethyst)". Retrieved 19 April 2018.
  4. ^ a b "Prasiolite". 28 October 2009. Retrieved 28 November 2010.
  5. ^ "Mineral Spectroscopy Server". California Institute of Technology. 11 June 2012. Retrieved 10 December 2012.
  6. ^ "Green Amethyst". GemSelect. Retrieved 10 December 2012.
  7. ^ "Green Quartz Meaning and Properties". n.d. Retrieved 21 October 2021.
  8. ^ Gems and Gemstones: Timeless Natural Beauty of the Mineral World By Lance Grande, Allison Augustyn, p.91