Blue Sapphire
Corundum var. Sapphire · Precious Gemstone
Crystal System
Trigonal, typically forming barrel-shaped, bipyramidal, or tabular crystals
Mineral Group
Oxides, specifically the hematite group
Chemical Formula
Al2O3 with trace amounts of Fe, Ti, Cr, V
Formation Process
Metamorphic and igneous processes, typically crystallizing in silica-deficient rocks like marble, syenite, or pegmatites under high temperature and pressure
About This Crystal
A small, deep blue tumbled or cabochon-cut gemstone displaying vitreous to adamantine luster, opaque to translucent transparency, and a rich indigo color characteristic of iron and titanium trace elements
Physical Characteristics
Deep blue body color, white streak, no true cleavage but exhibits parting on rhombohedral planes, conchoidal to uneven fracture, specific gravity of approximately 4.00, brittle tenacity, and inert to moderate orange-red fluorescence under UV
Optical Properties
Doubly refractive with uniaxial negative optical character, refractive indices ranging from 1.762 to 1.770, strong dichroism showing blue and greenish-blue or violet-blue from different angles
Hardness & Durability
Origin Region
Notable sources include Kashmir, Myanmar (Burma), Sri Lanka (Ceylon), Madagascar, Australia, and Thailand; forms in aluminum-rich metamorphic and igneous rocks
Hardness & Durability
Mohs hardness of 9, making it extremely durable and second only to diamond; excellent toughness and high resistance to scratching and chemical wear, suitable for daily jewelry wear
Care & Maintenance
Safe to clean with warm soapy water, ultrasonic cleaners, and steam cleaners unless heavily fractured or inclusion-filled; store separately to prevent scratching other gemstones
Rarity & Value
Ranges from common to extremely rare depending on origin, color saturation, and clarity; untreated natural stones with vivid saturation (like Kashmir or Burmese sapphires) command high collector prices, while heat treatment is standard and widely accepted
Special Characteristics
May exhibit asterism (star sapphire) due to rutile needle inclusions, color-change phenomena in certain varieties, or subtle silk and zoning patterns
Lore & History
Historically revered as a stone of wisdom, royalty, and divine favor, worn by clergy and kings; associated with the Third Eye and Throat chakras in modern metaphysical lore for promoting mental clarity and spiritual focus