Friday, December 9, 2016

Citrine Gemstone

What is Citrine?

Citrine is the yellow to orange variety of Quartz. Natural Citrine is not common; most Citrine on the gem market is produced by heat treating Amethyst and Smoky Quartz. It takes a relatively low temperature to change the colour light to golden yellow, and heating to higher temperatures will give the stone a darker yellow to brownish-red colour. The name Citrine is derived from the citron fruit, a yellow fruit similar to the lemon. (In fact, citron means "lemon" in several languages).

Citrine 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. 

Citrine Gemstone

Natural citrines are rare. Most commercial citrine is heat-treated amethyst or smoky quartz. Because the colour is now caused by finely distributed iron minerals (mostly hematite and goethite), heated amethyst is not a citrine in the strict sense. Quartz coloured by inclusions of any kind is not called a citrine.

History

Citrine is a transparent, yellow variety of Quartz, ranging in colour from pale to golden yellow, honey or almost brown, and may contain rainbow or sparkle inclusions. The name comes from the French word citron, meaning lemon. It was used as a gem in Greece as far back as 300 B.C., and because of its colour, is sometimes mistakenly referred to as Gold Topaz, Madeira or Spanish Topaz, or Safranite. Much of the commercial Citrine on the market is heat-treated Amethyst or Smoky Quartz that produces an enhanced Citrine colour, usually a deeper amber or orange-reddish shade. Most Natural Citrine is a pale yellow colour.

Properties of Citrine

Chemical FormulaSiO2
ColourYellow, Orange, Brown
Hardness7
Crystal SystemHexagonal
Refractive Index1.54 - 1.55
SG2.63 - 2.65
TransparencyTransparent
Double Refraction.009
LusterVitreous
CleavageIndiscernible
Mineral ClassQuartz