Blue Obsidian
Volcanic Glass var. Blue Obsidian · Decorative Stone and Semi-Precious Gemstone
Crystal System
Amorphous (Non-crystalline)
Mineral Group
Mineraloid
Chemical Formula
SiO2 (Amorphous Silicon Dioxide with various trace impurities like iron and magnesium)
Formation Process
Extrusive igneous process formed by the rapid cooling of viscous felsic lava rich in silica, preventing crystal growth.
About This Crystal
A polished, tumbled smooth, translucent deep blue stone with a glass-like vitreous luster, displaying internal light transmission and subtle color variation.
Physical Characteristics
Color ranges from deep teal to electric blue; white streak; no cleavage; sharp conchoidal fracture; specific gravity around 2.35 to 2.45; brittle tenacity; non-magnetic.
Optical Properties
Singly refractive (isotropic) due to its amorphous structure, transparent to translucent with a vitreous luster.
Hardness & Durability
Origin Region
Found in regions with volcanic activity including the United States (Oregon, California), Mexico, Iceland, and Japan.
Hardness & Durability
Mohs hardness of 5 to 5.5, relatively brittle with excellent conchoidal fracture making it prone to chipping if dropped; moderate wearability for jewelry if protected.
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid harsh chemicals, ultrasonic cleaners, and prolonged exposure to direct sunlight.
Rarity & Value
Common as a manufactured or treated product, though natural obsidian with genuine blue coloration is rare and often subject to commercial glass enhancement.
Special Characteristics
Displays a sharp conchoidal fracture typical of glass, high transparency under direct light, and a vibrant vitreous sheen.
Lore & History
Used historically by indigenous cultures for cutting tools and weapons; in modern metaphysical practices, blue obsidian is traditionally associated with the throat chakra, communication, and emotional healing.