Smoky quartz

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Smoky quartz crystal stage
Fabergé vase from 1898

Smoky quartz (or morion ) is a variety of the mineral quartz that has been colored gray-brown (smoke-colored) to black (morion) by natural or artificial gamma rays . Mostly, brown smoky quartz is transparent to translucent. Well-formed smoky quartz crystals are rarer than comparable rock crystals , but they are still found relatively often.

Etymology and history

The name smoky quartz goes back to the color of this quartz variety. The name Morion, which is also frequently used for the dark gray-brown to black variety, can be traced back to the Roman historian and naturalist Pliny . He called the mineral in his encyclopedia Naturalis historia (Book 37, Chapter 173) mormorion . In German-speaking countries, the name became Morion garbled .

properties

Irradiation of colorless quartz with ionizing rays (e.g. gamma rays ) leads to the formation of lattice defects or color centers . In the case of natural irradiation, radioactive minerals or elements in the surrounding rock are the cause of the formation of the color centers.

For chemical and physical properties see main article quartz .

Education and Locations

Smoky quartz mainly forms in granitic pegmatites , but can also arise in alpinotype quartz veins and in cavities ( geodes ) of volcanic rocks .

As a frequent mineral formation, smoky quartz can be found at many sites around the world, with almost 2400 sites documented so far (as of 2019). Crystals several meters in length are often discovered. One of the largest smoky quartz crystals discovered worldwide is a crystal found in Kazakhstan that weighs 77 tons.

Well-known find areas are among others in Australia , Brazil , Madagascar , Russia , Switzerland , Scotland , Ukraine and the United States .

use

Smoky quartz is only processed into gemstones and art objects . Occasionally, the name “Rauchtopaz” is found in the trade, although this is one of the forbidden trade names.

From aluminum-containing rock crystals (colorless quartz) it is relatively easy to produce smoky quartz by artificial irradiation, which is done in large quantities , especially with quartz from Arkansas (USA). The Arkansas location can therefore always be viewed as suspicious for smoky quartz. Smoke quartz produced by irradiation does not pose a risk, however, since no radioactive isotopes are produced in this process .

See also

literature

Web links

Commons : Smoky Quartz  - collection of images, videos and audio files

Individual evidence

  1. ↑ Hans Lüschen: The names of the stones. The mineral kingdom in the mirror of language . 2nd Edition. Ott, Thun 1979, ISBN 3-7225-6265-1 , p. 279-280 .
  2. ↑ Localities for Smoky Quartz. In: mindat.org. Hudson Institute of Mineralogy, accessed September 14, 2019 .
  3. ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia (=  Dörfler Natur ). Edition Dörfler im Nebel-Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 91-92 .
  4. ↑ Find location list for smoky quartz in the Mineralienatlas and Mindat
  5. ^ Precious stone etiquette from Prof. Leopold Rössler - smoky quartz. In: beyars.com. Retrieved September 14, 2019 .
  6. ↑ Bernhard brother embellished stones. Recognizing imitations and manipulations in gemstones and minerals . Neue Erde, Saarbrücken 2005, ISBN 3-89060-079-4 , p. 91 .