16.5.3: Citrine
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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 |
Figure 16.5.3.1: 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 a golden tone. Citrine has been credited with curing urinary tract infections, jaundice and kidney ailments. This is obviously a color association.