THE MATERIAL LIBRARY
Carnelian
Orange to red chalcedony colored by iron compounds.
Colors & patterns
Translucent orange, rust, red and reddish brown.
Typical origins
Sources include India, Brazil and Uruguay.
Hardness
6.5–7 on the Mohs scale.
Choosing & setting this material
A polished dome brings out its warm glow. Heating and dyeing can be used to modify color; confirm enhancement information when selecting a stone.
Care & cleaning
Clean gently with lukewarm water, a little mild soap and a soft cloth, then dry. Avoid steam, ultrasonic cleaners, harsh chemicals and sudden temperature changes, especially when treatments are unknown.
Origins above describe typical sources of the material, not the origin of an illustrated or stocked stone. Hardness measures scratch resistance, not resistance to breaking. Confirm the identity and treatments of the actual piece.
Further reading: Material reference · GIA: gem treatments