Carnelian
Chalcedony var. Carnelian (Cryptocrystalline Quartz) · Semi-Precious Gemstone
Crystal System
Trigonal (Hexagonal system with microcrystalline structure); Habit is usually massive or botryoidal in raw form, but here it is cut into a hexagonal prismatic point.
Mineral Group
Silicates (Tectosilicate group, Quartz family)
Chemical Formula
SiO2 (Silicon Dioxide) colored by impurities of Iron Oxide (Hematite)
Formation Process
Formation occurs via low-temperature hydrothermal processes where silica-rich fluids deposit within cavities of volcanic or sedimentary rocks over long periods.
About This Crystal
A translucent to semi-opaque variety of chalcedony displaying a vibrant range of orange, red, and brownish-red hues. This specimen features distinct white and pale orange banding (Agate-like zoning) with a vitreous to waxy luster.
Physical Characteristics
Color: Orange-red with white bands; Streak: White; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58–2.64; Fluorescence: Weak yellow-green or inert under UV.
Optical Properties
Refractive Index: 1.530–1.540; Birefringence: Up to 0.004; Optical character: Uniaxial positive; Lacks pleochroism due to microcrystalline nature.
Hardness & Durability
Origin Region
Major sources include India, Brazil, Uruguay, and Madagascar; typically found in volcanic cavities (vugs) and sedimentary environments.
Hardness & Durability
Mohs Hardness: 6.5–7; Excellent durability and toughness due to its compact microcrystalline structure; suitable for daily jewelry wear.
Care & Maintenance
Clean with warm soapy water and a soft brush. It is generally stable, but avoid harsh chemicals and prolonged exposure to high heat which can alter the iron oxide's oxidation state.
Rarity & Value
Common; Value is determined by color intensity and translucency. Natural deep red-orange is valued higher. Heat treatment of duller brownish stones to enhance orange tones is very common.
Special Characteristics
Displays distinct color zoning or banding typical of agates; the red color is derived from hematite (Fe2O3) inclusions distributed throughout the silica lattice.
Lore & History
Historically used in Ancient Egypt for amulets and seals, and notable in Roman signet rings. Traditionally associated with the Sacral Chakra, it is symbolically linked to courage, vitality, and creativity.