Carnelian
Quartz var. Carnelian · Semi-Precious Gemstone
Crystal System
Trigonal, microcrystalline (chalcedony variety), typically forming in massive, nodular, or botryoidal habits.
Mineral Group
Silicates, specifically Tectosilicates
Chemical Formula
SiO2
Formation Process
Hydrothermal and low-temperature sedimentary processes involving the deposition of silica-rich solutions within rock cavities, where microscopic quartz crystals (chalcedony) aggregate, colored by iron oxide impurities.
About This Crystal
This specimen is a small, smoothly polished cabochon displaying a vibrant, translucent to semi-translucent reddish-orange color with a waxy to vitreous luster and a smooth, curved surface typical of tumble-polished pocket stones.
Physical Characteristics
Color ranges from yellowish-orange to deep brownish-red; white streak; no cleavage; conchoidal fracture; specific gravity of approximately 2.60 to 2.65; brittle tenacity; displays no significant magnetism or strong natural fluorescence.
Optical Properties
Refractive index ranges from 1.530 to 1.540; doubly refractive (aggregate); generally non-pleochroic due to microcrystalline structure; exhibits a soft, internal glow rather than chatoyancy or asterism.
Hardness & Durability
Origin Region
Notable sources include India, Brazil, Madagascar, Egypt, and Uruguay. It forms primarily in silica-rich volcanic and sedimentary environments.
Hardness & Durability
Mohs hardness of 6.5 to 7; good toughness and durability for general jewelry use, resisting scratches from most common materials except quartz-bearing dust and harder minerals.
Care & Maintenance
Safe to clean with warm soapy water and a soft brush; avoid harsh chemical cleaners, prolonged extreme heat, and sudden temperature shocks; store separately from harder gems to prevent scratching.
Rarity & Value
Common to uncommon depending on color saturation and translucency; premium deep orange or red specimens command higher prices, though most tumbled pieces are inexpensive and widely accessible.
Special Characteristics
Often features subtle internal banding, cloudiness, or subtle color zoning caused by varying concentrations of iron oxide (hematite or limonite) micro-inclusions distributed throughout the chalcedony matrix.
Lore & History
Historically used in ancient Rome, Greece, and Egypt for signet rings, amulets, and royal burial items; traditionally associated with courage, vitality, motivation, and the sacral chakra in modern crystal healing.