Citrine
Citrine Starbrite Cut
18.24 carats
© johndyergems.com
The name Citrine is derived from its lemon yellow colour.
Citrine is sometimes very pale or almost colourless. Among deeper coloured stones may be seen wine-yellow, honey-yellow, and saffron-yellow specimens, while others have quite a pronounced brown tinge. Stones of a deep brownish-yellow colour are very similar to
topaz, and those of a fine golden-yellow are quite equal in beauty to yellow
topaz and can scarcely be distinguished on mere inspection from latter stone except by an expert.
Natural citrines are rare. Most commercial citrine is heat-treated
amethyst or
smoky quartz. Because the color is now caused by finely distributed iron minerals (mostly hematite and goethite), heated
amethyst is not a citrine in the strict sense.
Quartz colored by inclusions of any kind is not called a citrine.
General Information |
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A variety or type of: | Quartz |
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Chemical Formula | Michael O’Donoghue, Gems, Sixth Edition (2006) |
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Citrine Treatments |
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Routinely produced by heat-treatment of (smoky) amethyst: reddish tint, may show reddish-brown hematite inclusions (surrounded by crack). Non-dichroic unlike natural - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 7 |
Citrine Simulants |
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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.
Thin coatings of iron oxides on colourless quartz, as well as inclusions of yellow iron oxides ("limonite"), may simulate citrine. |
Physical Properties of Citrine |
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Mohs Hardness | 7Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
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Specific Gravity | 2.65Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
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Tenacity | BrittleWalter Schumann, Gemstones of the world (2001) |
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Cleavage Quality | NoneWalter Schumann, Gemstones of the world (2001) |
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Fracture | ConchoidalMichael O’Donoghue, Gems, Sixth Edition (2006) |
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Optical Properties of Citrine |
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Refractive Index | 1.544 to 1.553Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
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Optical Character | Uniaxial/+Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
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Birefringence | 0.009Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
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Pleochroism | Natural: weak; yellow - light yellow. Heat-treated: noneWalter Schumann, Gemstones of the world (2001) More from other references |
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Dispersion | 0.013Walter Schumann, Gemstones of the world (2001) |
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Chatoyancy | Star 6Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
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Colour |
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Colour (General) | Light yellow to dark yellow, gold-brownWalter Schumann, Gemstones of the world (2001) More from other references |
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Causes of Colour | Yellow to orange, O2-→Fe3+ charge transfer, various Al3+ related color centers.W. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011) |
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Transparency | Transparent,TranslucentUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
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Lustre | VitreousGemdat.org, Management Team (2012) |
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Fluorescence & other light emissions |
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Fluorescence (General) | NoneWalter Schumann, Gemstones of the world (2001) |
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Crystallography of Citrine |
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Crystal System | TrigonalUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
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Habit | Hexagonal prisms with pyramidsWalter Schumann, Gemstones of the world (2001) More from other references |
Further Information |
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Mineral information: | Citrine information at mindat.org |
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Significant Gem Localities |
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| Bolivia | |
| Laurs (2001, 2010) | | Brazil | |
| Macri et al. (2006) |
| Kievlenko E.Ya., Geology of gems, 2003, p. 113 | | Canada | |
| Sinkankas (1997) | | Madagascar | |
| Madagascar, extraLapis English No.1, 2001, p. 44 |
| Pezzotta (2001) |
| Danet (2009) | | Myanmar | |
| Ted Themelis (2008) Gems & mines of Mogok |
| Ted Themelis (2008) Gems & mines of Mogok | | Sri Lanka | |
| | | Uruguay | |
| Gilg et al. (2003) |
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