Carnelian
Quartz var. Carnelian · Semi-Precious Gemstone
Crystal System
Trigonal, massive or microcrystalline habit, frequently found as tumbled pebbles or nodular aggregates.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2
Formation Process
Hydrothermal and sedimentary deposition processes, precipitating from silica-rich groundwater within volcanic cavities at low temperatures.
About This Crystal
A small tumbled pebble with a warm reddish-orange to brownish-orange body color, featuring translucent areas and characteristic white chalcedonic banding and inclusions near the surface. The surface is smoothly polished with a waxy to vitreous luster.
Physical Characteristics
Color ranges from orange to reddish-orange; white streak; exhibits no true cleavage; conchoidal fracture; specific gravity of approximately 2.65; brittle tenacity; generally inert under UV light though some specimens may show slight fluorescence.
Optical Properties
Refractive index ranges from 1.544 to 1.553; doubly refractive with weak birefringence; typically translucent to semi-transparent; no significant pleochroism.
Hardness & Durability
Origin Region
India, Brazil, Madagascar, Uruguay, and the United States. Forms within cavities of volcanic rocks and hydrothermal environments.
Hardness & Durability
Mohs hardness of 7; good toughness and durability making it highly suitable for daily wear in jewelry; resistant to scratching by most household items.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid harsh chemicals and prolonged exposure to direct sunlight which can gradually fade the color; store separately from softer gems.
Rarity & Value
Common and widely available; value is determined by color saturation, translucency, and size, with deep, even reddish-orange hues commanding higher prices; heat treatment of ordinary chalcedony is occasionally used to enhance color.
Special Characteristics
Displays subtle color zoning and translucent banding typical of microcrystalline quartz varieties; exhibits fine micro-fibrous structure visible under magnification.
Lore & History
Historically used by ancient civilizations including the Egyptians, Romans, and Greeks for signet rings, talismans, and royal burial items; traditionally associated with courage, motivation, and vitality, linked primarily to the sacral chakra.