Blue Obsidian
Volcanic Glass var. Blue Obsidian · Semi-Precious Gemstone
Crystal System
Amorphous (Non-crystalline)
Mineral Group
Mineraloid
Chemical Formula
SiO2 with various impurities
Formation Process
Igneous, formed from rapidly cooling felsic lava where chemical constituents do not have time to crystalline.
About This Crystal
A polished spherical specimen displaying a vibrant, bright aqua-blue to turquoise color, with semi-translucent to transparent clarity and a smooth vitreous luster.
Physical Characteristics
Color is vivid blue, white streak, no cleavage, distinctly conchoidal fracture, specific gravity around 2.35 to 2.45, brittle tenacity.
Optical Properties
Singly refractive (isotropic), refractive index of approximately 1.48 to 1.51, no pleochroism.
Hardness & Durability
Origin Region
Mexico, USA, Iceland, Peru
Hardness & Durability
Mohs hardness of 5 to 5.5, relatively brittle, sensitive to sharp impacts and scratches, fair durability for jewelry if protected.
Care & Maintenance
Clean with mild soapy water and a soft cloth, avoid harsh chemical cleaners, ultrasonic cleaners, and prolonged direct sunlight.
Rarity & Value
Common; while natural blue obsidian exists in very small quantities with subtle tones, highly vibrant blue polished stones are often artificially colored or man-made glass.
Special Characteristics
Conchoidal fracture resulting in extremely sharp edges when broken; vividly colored specimens often display internal flow lines or tiny gas bubbles.
Lore & History
Associated traditionally with the throat chakra, communication, and emotional healing, though most vividly colored specimens on the market are spiritually valued for clarity and calm.