Carnelian Agate
Quartz var. Chalcedony (Carnelian/Agate) · Semi-Precious Gemstone and Decorative Stone
Crystal System
Trigonal, microcrystalline habit forming in botryoidal, nodular, or massive structures
Mineral Group
Silicates, subgroup Tectosilicates
Chemical Formula
SiO2
Formation Process
Hydrothermal and sedimentary deposition involving silica-rich groundwater filling cavities in volcanic or host rocks at low temperatures and pressures
About This Crystal
A polished, irregularly shaped specimen exhibiting translucent to opaque areas with distinct color zoning ranging from milky white to translucent chalcedony and rich reddish-brown or carnelian tones. It features a smooth, waxy luster and botryoidal internal growth patterns.
Physical Characteristics
Color includes reddish-brown, orange, white, and translucent zones; white streak; no cleavage; conchoidal fracture; specific gravity around 2.60 to 2.65; brittle tenacity; inert to moderate fluorescence under UV light depending on impurities.
Optical Properties
Refractive index ranges from 1.530 to 1.540; doubly refractive (uniaxial positive microcrystalline); generally non-pleochroic; vitreous to waxy luster.
Hardness & Durability
Origin Region
Found globally with notable sources in Brazil, India, Madagascar, Uruguay, and the USA
Hardness & Durability
Mohs hardness of 6.5 to 7; good toughness due to microcrystalline interlocking structure; stable under normal environmental conditions and suitable for most types of jewelry.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid harsh chemicals and prolonged exposure to extreme heat; store separately from softer materials to prevent scratching.
Rarity & Value
Common to uncommon depending on color saturation and clarity; valued for carvings and cabochons; generally affordable, though top-grade deep carnelian commands higher collector value.
Special Characteristics
Banding patterns, color zoning, and a smooth botryoidal or pocketed formation typical of chalcedony nodules.
Lore & History
Historically used by ancient civilizations including the Egyptians, Romans, and Greeks for seals, signet rings, and amulets for courage and vitality. In modern crystal healing, it is traditionally associated with the sacral chakra to promote motivation, creativity, and confidence.