Carnelian
Chalcedony var. Carnelian (Quartz group) · Semi-Precious Gemstone / Decorative Stone
Crystal System
Trigonal (Hexagonal system); typically occurs in microcrystalline or cryptocrystalline massive habits, often found as pebbles or nodules.
Mineral Group
Silicates (Subgroup: Tectosilicates)
Chemical Formula
SiO2 (Silicon Dioxide) colored by iron oxide (Hematite) impurities
Formation Process
Formation occurs via low-temperature hydrothermal precipitation of silica-rich fluids in cavities, veins, or groundwater environments (Sedimentary/Metamorphic context).
About This Crystal
A translucent to semi-opaque microcrystalline quartz. This specimen displays a vibrant orange-red to reddish-brown hue with a vitreous to waxy luster. It has been tumble-polished into a smooth, rounded shape.
Physical Characteristics
Color: Orange to deep red; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.58-2.64; Tenacity: Brittle; Fluorescence: Weak to none.
Optical Properties
Refractive Index: 1.530-1.540; Birefringence: Up to 0.004; Optical character: Uniaxial positive; Typically displays no pleochroism due to microcrystalline structure.
Hardness & Durability
Origin Region
Prominent sources include India (Gujarat), Brazil, Uruguay, Madagascar, and Egypt. Often found in volcanic cavities and sedimentary environments.
Hardness & Durability
Mohs Hardness: 6.5-7. Excellent durability and toughness for jewelry use as it lacks cleavage planes.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid harsh chemicals and prolonged exposure to high heat. Safe for ultrasonic cleaners if no significant internal fractures exist.
Rarity & Value
Common; Value is determined by color saturation (deep red/orange is preferred) and translucency. Heat treatment is common to enhance color by oxidizing iron inclusions.
Special Characteristics
Often shows subtle banding or cloud-like inclusions under magnification. Translucency varies across the stone, sometimes revealing darker iron-rich spots.
Lore & History
Used since the Neolithic age for beads; highly prized in Ancient Egypt as the 'Sunset Stone' for protection. Traditionally associated with the Sacral Chakra, vitality, and motivation in lore.