Carnelian Agate
Quartz var. Chalcedony (Carnelian) · Semi-Precious Gemstone
Crystal System
Trigonal, microcrystalline habit usually occurring as masses, nodular aggregates, or tumbled stones
Mineral Group
Silicates (Tectosilicates)
Chemical Formula
SiO2
Formation Process
Low-temperature hydrothermal deposition or sedimentary precipitation in silica-rich groundwater cavities
About This Crystal
Tumbled smooth stone featuring translucent to opaque orange, reddish-orange, and pinkish hues with distinctive polka-dot or orbicular inclusions and translucent banding
Physical Characteristics
Color ranges from pale orange to deep reddish-brown; white streak; no cleavage; conchoidal fracture; specific gravity around 2.60 to 2.65; brittle tenacity; generally inert to weak fluorescence under UV light
Optical Properties
Singly or doubly refractive microcrystalline aggregate with a refractive index of approximately 1.530 to 1.540; vitreous to waxy luster
Hardness & Durability
Origin Region
Found globally with notable sources in India, Brazil, Madagascar, Uruguay, and the United States
Hardness & Durability
Mohs hardness of 6.5 to 7; good toughness and durability making it highly suitable for everyday jewelry wear
Care & Maintenance
Can be cleaned safely with warm soapy water and a soft brush; avoid harsh chemicals and prolonged exposure to direct sunlight to prevent fading
Rarity & Value
Common and widely available; value depends primarily on color saturation, clarity, and patterning, with vibrant deep orange or red specimens commanding higher prices; heat treatment is occasionally used to enhance color
Special Characteristics
Features orbicular dot patterns and translucent chalcedony areas interspersed with iron oxide inclusions
Lore & History
Historically used by ancient Egyptians, Romans, and Greeks for signet rings and amulets; traditionally associated with courage, vitality, and motivation in crystal healing lore