Carnelian
Quartz var. Carnelian · Semi-Precious Gemstone / Decorative Stone
Crystal System
Trigonal; Microcrystalline (Cryptocrystalline) aggregations typically appearing massive or as water-worn pebbles.
Mineral Group
Silicates (Tectosilicate subgroup), Chalcedony species
Chemical Formula
SiO2 (Silicon Dioxide) colored by iron oxide (Hematite) impurities
Formation Process
Sedimentary or Hydrothermal; forms from the precipitation of silica-rich fluids in rock cavities at relatively low temperatures.
About This Crystal
A translucent to semi-opaque variety of chalcedony. This specimen shows a waxy luster with a characteristic orange-red to brownish-red hue. It features a rounded, tumbled appearance with some surface scuffing and white bruising common to microcrystalline quartz.
Physical Characteristics
Color: Orange to deep red. Streak: White. Cleavage: None. Fracture: Conchoidal. Specific Gravity: 2.58-2.64. Luster: Vitreous to waxy. Fluorescence: Typically inert.
Optical Properties
Refractive Index: 1.530-1.540. Birefringence: Up to 0.009. Pleochroism: None. Optical Nature: Aggregately polarizes (singly refractive/cryptocrystalline).
Hardness & Durability
Origin Region
Notable sources include Brazil, India, Madagascar, Uruguay, and Egypt. It is found in volcanic cavities and sedimentary environments.
Hardness & Durability
Mohs Hardness: 6.5 to 7. Toughness is excellent due to its microcrystalline structure, making it very durable for jewelry and carvings.
Care & Maintenance
Clean with warm soapy water and a soft brush. Generally stable, but heat treatment can sharpen colors; avoid extreme temperature shocks and chemicals like hydrofluoric acid.
Rarity & Value
Common rarity. Value is determined by color uniformness, translucency, and size. Bright, reddish-orange translucent pieces are most prized. Often heat-treated to enhance red tones.
Special Characteristics
Can display faint banding (transitioning into Agate). Some specimens may exhibit slight adularescence or a 'glow' when backlit due to its fibrous structure.
Lore & History
Known since the Bronze Age; used by Ancient Egyptians in amulets and by Romans for seal rings because wax doesn't stick to it. Traditionally associated with courage, vitality, and the sacral chakra.