Also known as cornelian, this translucent, reddish orange variety of chalcedony was once thought to still the blood and calm the temper. Its various shades of red are due to the presence of iron oxide. Stones may be uniformly colored or faintly banded.
The best carnelian is from India, where it is placed in the sun to change brown tints to red.
Most carnelian available on the market is stained chalcedony from Brazil or Uruguay.