Vermarine

Not to be confused with Praseolite.
Vermarine (quartz variety)

Raw natural vermarine
General
Category Oxide mineral
Crystal system Trigonal
Identification
Color shades of green
Crystal habit Hexagonal prisms
Cleavage None
Fracture Conchoidal[1]
Tenacity brittle[1]
Mohs scale hardness 7 – lower in impure varieties[1]
Diaphaneity Transparent to nearly opaque
Specific gravity 2.65
Refractive index 1.544 to 1.553[2]
Birefringence 0.009[3]
Ultraviolet fluorescence none

Vermarine, green quartz or prasiolite is a green form of quartz, a silicate mineral chemically silicon dioxide. Vermarine is one of several quartz varieties.

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

The term prasiolite is also rarely found as praziolite. Prasiolite can be confused with the similarly colored praseolite which results from the heat treatment of iolite, a variety of cordierite.[5] Most vermarine sold is used in jewellery settings, where it can substitute for far more expensive precious gemstones.

It is a rare stone in nature; artificially produced vermarine is heat treated amethyst.[4] Most amethyst will turn yellow or orange when heated producing citrine. But some amethyst will turn green when treated. Currently, almost all vermarine on the market results from a combination of heat treatment and ionizing radiation.[6]

Green quartz is sometimes incorrectly called green amethyst, which is not an acceptable name for the material, the proper terminology being prasiolite.[7] It is actually against Federal Trade Commission Guidelines to call vermarine "green amethyst." Other names for green quartz are vermarine, greened amethyst, or lime citrine.

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 vermarine is a very light, translucent green. Darker green quartz is generally the result of artificial treatment.[8]

See also

References

  1. 1 2 3 Prasiolite on Gemdat.org
  2. ↑ Lazarelli. Blue Chart Gem Identification. p. 7.
  3. ↑ http://www.galleries.com/Prasiolite
  4. 1 2 "Prasiolite". quarzpage.de. 28 October 2009. Retrieved 28 November 2010.
  5. ↑ "Prasiolite". Amethyst Galleries' Mineral Gallery.
  6. ↑ "Mineral Spectroscopy Server". California Institute of Technology. 11 June 2012. Retrieved 10 December 2012.
  7. ↑ "Green Amethyst". GemSelect. Retrieved 10 December 2012.
  8. ↑ Gems and Gemstones: Timeless Natural Beauty of the Mineral World By Lance Grande, Allison Augustyn, p.91


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