Carnelian
Quartz var. Carnelian · Semi-Precious Gemstone
Crystal System
Trigonal, forming in microcrystalline aggregates known as chalcedony
Mineral Group
Silicates
Chemical Formula
SiO2
Formation Process
Low-temperature hydrothermal or sedimentary deposition, where silica-rich groundwater precipitates microcrystalline quartz within cavities, with iron oxide impurities imparting the orange-red color
About This Crystal
A polished sphere of translucent to sub-translucent chalcedony displaying warm amber, brownish-orange, and reddish hues with subtle internal cloudiness and cloudy banding typical of cryptocrystalline quartz
Physical Characteristics
Orange to reddish-brown body color, white streak, conchoidal fracture with no true cleavage, specific gravity of approximately 2.60 to 2.65, and a vitreous to waxy luster
Optical Properties
Singly refractive aggregate behavior with microscopic double refraction, refractive index around 1.530-1.540, and no significant pleochroism
Hardness & Durability
Origin Region
Brazil, India, Madagascar, and Uruguay, typically forming in volcanic and sedimentary rock cavities
Hardness & Durability
Mohs hardness of 6.5 to 7, good toughness due to microcrystalline interlocking structure, making it durable and suitable for general jewelry use
Care & Maintenance
Clean with warm soapy water using a soft brush, avoid harsh chemical cleaners or prolonged exposure to direct, intense sunlight to prevent fading
Rarity & Value
Common and widely accessible, with value depending on color saturation, clarity, and size, ranging from affordable tumbled stones to moderately priced collector carvings
Special Characteristics
May exhibit subtle cloud-like color zoning or internal banding under strong backlighting, caused by varying concentrations of dispersed iron oxide inclusions
Lore & History
Historically used in ancient Rome, Egypt, and Greece for signet rings and talismans, traditionally associated with courage, vitality, motivation, and the sacral chakra in crystal healing lore