Carnelian

Carnelian is the red, orange, or amber variety of Chalcedony. Though often a solid color, it may also be streaked, in which case it would be jointly classified as both Agate and Carnelian. Carnelian is an ancient gemstone, having been used as gem material since antiquity. Although still used a gemstone today, its significance and value has been diminished since the ancient times.

Chemical Formula	SiO2
Color	Red, Orange
Hardness	7
Crystal System	Hexagonal
Refractive Index	1.54Â -Â 1.55
SG	2.63Â -Â 2.65
Transparency	Transparent to nearly opaque
Double Refraction	.009
Luster	Vitreous
Cleavage	None
Mineral Class	Quartz (Chalcedony)