Carnelian
Quartz var. Carnelian · Semi-Precious Gemstone; Mineral Specimen
Crystal System
Trigonal (Hexagonal); usually found in massive or microcrystalline (cryptocrystalline) habits with no visible external crystal faces.
Mineral Group
Silicates; Tectosilicate (Chalcedony species)
Chemical Formula
SiO2 (Silicon Dioxide) with Iron Oxide (Fe2O3) impurities
Formation Process
Formation occurs via hydrothermal activity where silica-rich fluids deposit in cavities (vesicles) of volcanic rocks or sedimentary layers at relatively low temperatures.
About This Crystal
A translucent to semi-opaque microcrystalline quartz. The specimen displays a warm orange to reddish-brown hue, a waxy to vitreous luster, and a smooth, tumbled surface resulting in a rounded, pebble-like shape.
Physical Characteristics
Color: Orange, red, or brownish-red. Streak: White. Cleavage: None. Fracture: Conchoidal. Specific Gravity: 2.58–2.64. Fluorescence: Generally inert, but may show weak yellow-green under UV.
Optical Properties
Refractive Index: 1.530–1.540. Birefringence: 0.004–0.009. Pleochroism: None. Optical Nature: Doubly refractive aggregated. Usually lacks distinctive phenomena like chatoyancy.
Hardness & Durability
Origin Region
Brazil, India, Uruguay, Madagascar, and Namibia; typically found in volcanic areas and sedimentary environments.
Hardness & Durability
Mohs Hardness: 6.5–7. Toughness: Good (due to microcrystalline structure). Highly stable and excellent for daily jewelry wear.
Care & Maintenance
Safe for cleaning with warm soapy water and soft brushes. Avoid harsh chemicals and sudden extreme heat. Generally stable under sunlight.
Rarity & Value
Common rarity. Value is determined by color uniformness and translucency. Bright 'pigeon blood' reds are most prized. Often heat-treated to enhance iron-induced color.
Special Characteristics
Subject to color zoning; can contain faint banding characteristic of its relation to agate. May show 'cloudy' inclusions of more opaque chalcedony.
Lore & History
Used since the Neolithic period; highly prized in Ancient Egypt for amulets and in Roman times for signet rings (seal stones). Traditionally associated with courage, vitality, and the sacral chakra.