Citrine

Citrine
Chemical composition	Silicon dioxide SiO2
Crystal system	Trigonal
Habit	Prismatic
Cleavage	Poor
Fracture	Conchoidal
Hardness	7
Optic nature	Uniaxial +
Refractive index	1.544 - 1.553
Birefringence	0.009
Dispersion	Low, 0.013
Specific gravity	2.63 - 2.65
Lustre	Vitreous
Pleochroism	Weak to distinct

Citrine oval faceted on Madiera Citrine Crystals.
Photo courtesy of Barbra Voltaire

Citrine is a yellow or golden variety of quartz. Most citrine available today is heat-treated amethyst. When amethyst is heated to about 482.2 degrees Celsius, it alters to to a golden tone. Citrine has been credited with curing urinary tract infections, jaundice and kidney ailments. This is obviously a color association.

Inclusion Images: Click on Image for Full Size

Citrine showing color banding.This stone was originally an amethyst which was heat treated.
Photo courtesy of Conny Forsberg