Carnelian
Quartz var. Carnelian · Semi-Precious Gemstone / Ornamental Stone
Crystal System
Trigonal, typically occurring as a microcrystalline aggregate (chalcedony) forming in massive, nodular, or tumbled pebble habits
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2
Formation Process
Low-temperature hydrothermal deposition or groundwater circulation in silica-rich volcanic or sedimentary environments
About This Crystal
A small, tumbled, orange-to-reddish-orange gemstone specimen with a smooth, polished surface, translucent to opaque clarity, and a waxy to vitreous luster exhibiting subtle internal color zoning and minor natural inclusions
Physical Characteristics
Orange to reddish-brown body color, white streak, conchoidal fracture, lack of discernible cleavage, specific gravity of approximately 2.65, brittle tenacity, and typically inert under UV light
Optical Properties
Refractive index ranging from 1.544 to 1.553, uniaxial positive optical character, double refraction, and no significant pleochroism due to its microcrystalline nature
Hardness & Durability
Origin Region
India, Brazil, Madagascar, Uruguay, and the United States, typically found in volcanic cavities and sedimentary alluvial deposits
Hardness & Durability
Mohs hardness of 7, good toughness making it durable for daily wear in jewelry, resistant to scratching by most common materials except quartz or harder minerals
Care & Maintenance
Safe to clean with warm soapy water and a soft brush, avoid harsh chemical cleaners, prolonged direct sunlight to prevent potential color fading, and ultrasonic cleaners
Rarity & Value
Common to uncommon depending on color saturation and clarity, value is generally low to moderate, and heat treatment of lighter agates is commonly used to enhance the reddish-orange color
Special Characteristics
Microfibrous chalcedony structure exhibiting characteristic cloudy or striped color distribution caused by finely dispersed iron oxide (hematite or limonite) impurities
Lore & History
Historically used by ancient civilizations including the Egyptians, Romans, and Greeks for signet rings, talismans, and burial offerings symbolizing courage and vitality, and traditionally associated with the sacral chakra in modern crystal healing