Citrine

Citrine is a naturally occurring colour variety of Quartz, composed of silicon dioxide, SiO₂. Its colours range from very pale yellow and lemon through golden yellow and orange, sometimes grading into smoky or brownish tones. Unlike Golden Healer Quartz or other ferruginous Quartz, genuine Citrine is not simply clear Quartz coated or visibly stained by iron minerals. The colour belongs to the Quartz itself and is associated with structural defects and trace-element-related colour centres within the crystal. Mindat notes that natural Citrine colour is still scientifically complex and that more than one mechanism may be involved. Mindat Natural Citrine is considerably less common than Clear Quartz or Amethyst. For that reason, a large amount of the yellow-orange Quartz sold commercially as Citrine is actually Amethyst that has been deliberately heated, altering its purple colour to yellow, orange or brown. Heat-treated Amethyst is still genuine Quartz, but it should be disclosed as treated material rather than represented as naturally occurring Citrine.