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Roger Weller, geology instructor                                     

wellerr@cochise.edu
Quartz Family Gemstones-by Audrey LaClair
                            
                          Citrine

Citrine is referred to as any cluster or quartz crystal that is yellow or orange in color.  It gets it's name from the French word citron, which means lemon.  And since it usually has a lemon color, it was named citrine.

 


photo by R.Weller

 

Most citrine is amethyst or smoky quartz that has been exposed to extreme heat.  If amethyst or smoky quartz is exposed long enough, it will turn a yellow color.  But often a synthetically heated quartz will have orange or reddish tints, unlike natural citrine which is a pale yellow.  It is rare to find natural citrine, because most is heat treated.  Because it is so readily available, it is relatively inexpensive. 

 

"Citrine is recognized by its color, crystal habit, occurrence, hardness, glassy luster, conchoidal fracture and lack of cleavage"
http://www.mineralminers.com/html/citminfo.htm
 

Most citrine is mined in Brazil, but it can also be found in Spain, the former USSR, and Madagascar.  In the USA it is found in Colorado, California, Georgia, and Nevada.

  


photo by R.Weller

 

PHYSICAL PROPERTIES
 

        Citrine Chemical composition: SiO2 (minor Fe3+ impurities cause citrine's color)

        Class: tectosilicate

        Crystal system: Hexagonal-R; 32 (trigonal-trapezohedral)

        Crystal habit: Macroscopic crystals occur as horizontally striated hexagonal prisms terminated by a combination of positive and negative rhombohedrons forming six sided pyramids. Citrine also occurs as drusy masses showing only the rhobohedral terminations. It can also be massive.

        Twinning: Dauphine twin with c the twin axis, Brazil twin with {1120} the twin plane

        Specific gravity: 2.65

        Index of refraction: 1.54-1.55

        Birefringence: 0.009

        Pleochroism: perceptible

        Hardness: 7

        Color: shades of yellow to reddish-orange

        Luster: vitreous

        Transparency: transparent to translucent

        Cleavage: none

        Fracture: conchoidal

        Streak: white

From (http://www.mineralminers.com/html/citminfo.htm)
 

References:

http://www.mineralminers.com/html/citminfo.htm
http://www.gemstone.org/gem-by-gem/english/citrine.html
http://mineral.galleries.com/minerals/gemstone/citrine/citrine.htm
http://www.jewelrymall.com/stones/citrine.html
http://www.jewelrymall.com/stones/citrine.html