Quartz main content.


Part of Hall of Gems.


Quartz SiO2

The water-clear quartz known as rock crystal was believed by the ancient Greeks to be permanently frozen water. Magicians through the centuries used it as crystal balls to contemplate the future.

Color variations of quartz depend on the oxidation state of traces of iron. Amethyst ranges from pale purple to dark violet, with color proportional to iron content and often with alternate triangular sectors of purple and white due to twinning. Named for the Greek word meaning “not drunken,” the stone was thought to protect the wearer from effects of alcohol. Mythology also i