Carnelian is one of the microcrystalline varieties of quartz. The name of the mineral derives from a Latin word carneulus, meaning color of the body.

Many stones sold as carnelian are in fact dyed agates. To tell an authentic stone from an imitation, one should look examine it closely against the light; imitations have visible boundaries between the lines of color. Carnelian's color can also be intensified by exposing it to sunlight.^[1]