Carnelian
Chalcedony (cryptocrystalline Quartz) var. Carnelian · Semi-Precious Gemstone; Decorative Stone
Crystal System
Trigonal (specifically hexagonal-system cryptocrystalline aggregates), appearing massive or in microcrystalline fibers
Mineral Group
Silicates (Tectosilicate group, Quartz family)
Chemical Formula
SiO2 (Silicon Dioxide) with impurities of Iron Oxide (Hematite)
Formation Process
Forms at low temperatures in volcanic rocks (cavities/vughs) or sedimentary environments through the deposition of silica from groundwater
About This Crystal
A translucent to semi-opaque variety of chalcedony. It features a waxy to vitreous luster and typically appears in shades of reddish-orange, brownish-red, or pale orange. This specific specimen is a 'tumble-polished' stone with a smooth, rounded surface.
Physical Characteristics
Color: Orange-red; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.58–2.64; Fluorescence: Often inert, but can show weak yellow-white under LWUV
Optical Properties
Refractive Index: 1.530–1.540; Birefringence: Up to 0.004; Pleochroism: None; Optical Character: Uniaxial positive (aggregate)
Hardness & Durability
Origin Region
India (Guirat), Brazil, Uruguay, Madagascar, and USA (Oregon/Washington)
Hardness & Durability
Mohs Hardness: 6.5–7.0; Toughness: Very good due to microcrystalline structure; Stability: Stable to light, but high heat can turn it more red or brownish
Care & Maintenance
Safe to clean with warm soapy water and a soft brush. Ultrasonic cleaners are generally safe but avoid harsh chemicals. Store away from harder gems like Topaz or Sapphire to prevent scratching.
Rarity & Value
Common; Value is determined by color saturation and translucency. Bright, clear orange-reds are most prized. Often subjected to heat treatment to enhance the red iron-oxide color.
Special Characteristics
When held to the light, color distribution can appear cloudy or mottled. It lacks the banding found in Agate but shares the same chemical makeup.
Lore & History
Historically used in Ancient Egypt for amulets and signet rings to signify courage. Culturally associated with the sacral chakra and believed to stimulate creativity, motivation, and endurance in traditional lore.