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Citrine

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System:
Trigonal
Colour:
Yellow - Orange
Lustre:
Vitreous
Hardness:
7
Name:
From citrina (color as yellow as citron).
A variety of Quartz

A yellow to yellow-orange or yellow-green variety of quartz.

A yellow-green citrine crystal with smoky phantoms.
A cut natural citrine from Norway
A natural citrine from Salamanca, a classic citrine locality
A yellow-green citrine crystal with smoky phantoms.
A cut natural citrine from Norway
A natural citrine from Salamanca, a classic citrine locality
A yellow-green citrine crystal with smoky phantoms.
A cut natural citrine from Norway
A natural citrine from Salamanca, a classic citrine locality

The cause of the color is still under debate. At least some citrine is colored by aluminum-based and irradiation-induced color centers related to those found in smoky quartz (Lehmann, 1972; Maschmeyer et al., 1980). Accordingly, transitions to smoky quartz ("smoky citrine") exist, many citrines show smoky phantoms. Like smoky quartz, these types of citrines pale when heated above 200-500°C and turn yellow again when irradiated (Lehmann, 1970). There appear to be at least two types of yellow Al-based color centers with different thermal stability (Schmetzer, 1988). Since the yellow color centers are often more stable than the smoky color centers, some smoky quartz can be turned into citrine by careful heating (Nassau and Prescott, 1977). Natural citrine as well as citrine produced by heating smoky quartz is dichroic in polarized light.


It has also been suggested that iron is the cause of color, as artificial crystals grown in a iron-bearing solution turn out yellow. However, the dichroic behavior of the lab-grown crystals differs from that in natural citrine (Rossmann, 1994).

Dichroism of citrine (right) compared to smoky quartz (left) and heated amethyst (center)
Thermal behaviour of citrine (two crystals in the center), compared to heated amethyst and amethyst, when heated to 380°C
An amethyst geode cut into 2 halves, the right one was heated to turn the amethyst into "citrine".
Dichroism of citrine (right) compared to smoky quartz (left) and heated amethyst (center)
Thermal behaviour of citrine (two crystals in the center), compared to heated amethyst and amethyst, when heated to 380°C
An amethyst geode cut into 2 halves, the right one was heated to turn the amethyst into "citrine".
Dichroism of citrine (right) compared to smoky quartz (left) and heated amethyst (center)
Thermal behaviour of citrine (two crystals in the center), compared to heated amethyst and amethyst, when heated to 380°C
An amethyst geode cut into 2 halves, the right one was heated to turn the amethyst into "citrine".

Note: Natural citrine is very rare. Large quantities of amethyst, usually of lesser quality, are heated to turn it yellow or orange and sold as "citrine." Because the color is now caused by finely distributed iron minerals (mostly hematite and goethite), heated amethyst is not citrine in the strict sense, and also shows no dichroism in polarized light.
Thin coatings of iron oxides on colourless quartz, as well as inclusions of yellow iron oxides ("limonite"), may simulate citrine.

Quartz colored by inclusions, or coatings, of any kind is not called citrine.


Visit gemdat.org for gemological information about Citrine.

Classification of Citrine

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Physical Properties of Citrine

Vitreous
Colour:
Yellow - Orange
Comment:
dichroic
Hardness (Mohs):
7

Crystallography of Citrine

Crystal System:
Trigonal

Other Names for Citrine

Name in Other Languages:
Basque:Zitrino
Bulgarian:Цитрин
Dutch:Citrien
Finnish:Sitriini
French:Citrine
Hungarian:Citrin
Latvian:Citrīns
Lithuanian:Citrinas
Polish:Cytryn
Portuguese:Citrino
Romanian:Citrin
Russian:Цитрин
Simplified Chinese:黃水晶
黄晶
Slovak:Citrín
Swedish:Citrin
Turkish:Sitrin

Other Information

Health Risks:
Citrine is a variety of quartz which is usually quite harmless unless broken or powdered. Broken crystals and masses may have razor-sharp edges that can easily cut skin and flesh. Handle with care. Do not grind dry since long-term exposure to finely ground powder may lead to silicosis.

References for Citrine

Reference List:
Georgius Agricola (1546) "De Natura Fossilium" (Book VI). Dover reprint Mark Chance Bandy & Jean A. Bandy translation Dover Publications p. 120

Dana, 1892, 187 - "Syst. Min. 6th Ed"

Chudoba, K. F. (1962) Some relations between the causes of amethyst, smoky quartz, and citrine colors as given by modern science. Mineralogicheskii Sbornik (Lvov): 16: 91-105.

Samoilovich, M.I., Tsinober, L.I., Kreishop, V.N. (1969) The nature of radiation-produced citrine coloration in quartz. Soviet Physics-Crystallography: 13: 626-628.

Lehmann, G. (1972) Yellow color centers in natural and synthetic quartz. Physik der Kondensierten Materie: 13: 297-306.

Nassau, K., Prescott, B.E. (1977) Smoky, blue, greenish yellow, and other irradiation-related colors in quartz. Mineralogical Magazine: 41: 301-312.

Maschmeyer, D., Niemann, K., Hake, K., Lehmann, G., Räuber, A. (1980) Two modified smoky quartz centres in natural citrine. Physics and Chemistry of Minerals: 6: 145-156

Schmetzer, K. (1988) Thermal stability of yellow color centers in natural citrine. Neues Jahrbuch für Mineralogie, Monatshefte: 2: 71-80.

Rossman, G.R. (1994) Colored varieties of the silica minerals. In: Reviews in Mineralogy, Vol.29, Silica - Physical behavior, geochemistry and materials applications, Mineralogical Society of America.

Pan, Y., Nilges, M.J., Mashkovtsev, R.I. (2008) Radiation-induced defects in quartz. II. Single-crystal W-band EPR study of a natural citrine quartz. Physics and Chemistry of Minerals: 35: 387-397.

Internet Links for Citrine

Specimens:
The following Citrine specimens are currently listed for sale on minfind.com.

Localities for Citrine

map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
Mineral and/or Locality  
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