Carnelian
Quartz var. Carnelian · Semi-Precious Gemstone and Decorative Stone
Crystal System
Trigonal, typically forming as microcrystalline quartz (chalcedony) aggregates in nodular, botryoidal, or massive habits.
Mineral Group
Silicates, specifically Tectosilicates
Chemical Formula
SiO2
Formation Process
Hydrothermal and sedimentary processes involving silica-rich groundwater depositing microcrystalline quartz within cavities and fractures of host rocks at low temperatures.
About This Crystal
A small, tumbled, and polished specimen showing translucent to semi-translucent properties with banded reddish-orange and white coloration, characteristic of chalcedony with iron oxide inclusions.
Physical Characteristics
Colors range from pale orange to deep brownish-red; white streak; exhibits conchoidal fracture with no true cleavage; specific gravity around 2.65; vitreous to waxy luster; brittle tenacity.
Optical Properties
Singly to doubly refractive with aggregate birefringence typical of microcrystalline quartz; refractive index around 1.543 to 1.553; non-pleochroic.
Hardness & Durability
Origin Region
Found globally with notable sources in India, Brazil, Madagascar, Uruguay, and the United States. Forms within volcanic and sedimentary rocks.
Hardness & Durability
Mohs hardness of 7, making it durable and suitable for various types of everyday jewelry including rings and bracelets; resistant to scratching by most common materials.
Care & Maintenance
Safe to clean with warm soapy water and a soft brush; avoid harsh chemicals and prolonged exposure to direct sunlight which can sometimes fade certain dyed or heat-treated varieties; ultrasonic and steam cleaning are generally safe.
Rarity & Value
Common to uncommon depending on the saturation and clarity of the orange-red color; widely affordable, though high-transparency natural specimens can command higher prices. Heat treatment of common grey chalcedony is frequently used to enhance color.
Special Characteristics
Often displays subtle banding patterns and translucent color zoning caused by varying concentrations of iron oxide and hydroxide impurities such as hematite and goethite.
Lore & History
Historically used in ancient civilizations including Ancient Egypt, Rome, and Greece for signet rings, talismans, and burial offerings to ensure safe passage into the afterlife. In modern crystal healing, it is associated with the sacral chakra, vitality, and motivation, though these are traditional beliefs rather than scientific claims.