Citrine Starbrite Cut
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.
colored by inclusions of any kind is not called a citrine.
|A variety or type of:||Quartz|
|Chemical Formula||Gems, Sixth Edition (2006) , |
|Photos of natural/un-cut material from mindat.org|
|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|
|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|
|Mohs Hardness||7Blue Chart Gem Identification (2010) , |
|Specific Gravity||2.65Gemmological Tables (2004) , |
|Tenacity||BrittleGemstones of the world (2001) , |
|Cleavage Quality||NoneGemstones of the world (2001) , |
|Fracture||ConchoidalGems, Sixth Edition (2006) , |
|Optical Properties of Citrine|
|Refractive Index||1.544 to 1.553Blue Chart Gem Identification (2010) , |
|Optical Character||Uniaxial/+Gemmological Tables (2004) , |
|Birefringence||0.009Gemmological Tables (2004) , |
|Pleochroism||Natural: weak; yellow - light yellow. Heat-treated: noneGemstones of the world (2001) , More from other references|
|Dispersion||0.013Gemstones of the world (2001) , |
|Chatoyancy||Star 6Blue Chart Gem Identification (2010) , |
|Colour (General)||Light yellow to dark yellow, gold-brownGemstones of the world (2001) , More from other references|
|Causes of Colour||Yellow to orange, O2-→Fe3+ charge transfer, various Al3+ related color centers.Pragmatic Spectroscopy For Gemologists (2011) , |
|Transparency||Transparent,TranslucentGemmological Tables (2004) , |
|Lustre||VitreousManagement Team (2012) , |
|Fluorescence & other light emissions|
|Fluorescence (General)||NoneGemstones of the world (2001) , |
|Crystallography of Citrine|
|Crystal System||TrigonalGemmological Tables (2004) , |
|Habit||Hexagonal prisms with pyramidsGemstones of the world (2001) , More from other references|
|Mineral information:||Citrine information at mindat.org|
|Significant Gem Localities|