Sapphire
Corundum var. Sapphire · Precious Gemstone
Crystal System
Trigonal, typically forming barrel-shaped, bipyramidal, or tabular hexagonal prisms
Mineral Group
Oxides
Chemical Formula
Al2O3 with trace amounts of Fe, Ti, Cr, V
Formation Process
Igneous in silica-deficient rocks like syenites and pegmatites, or Metamorphic in marble and gneiss through regional or contact metamorphism under high temperatures and pressures
About This Crystal
The jewelry piece features a central greyish or included diamond flanked by smaller dark blue round-cut sapphires set in a metallic band, exhibiting vitreous to adamantine luster and translucent to transparent clarity depending on the stone
Physical Characteristics
Color ranges from deep blue to colorless, grey, yellow, pink, and green with a white streak; crystal habit is typically prismatic; no true cleavage, instead exhibiting parting along specific planes; conchoidal fracture; specific gravity around 4.0; brittle tenacity; highly resistant to scratching
Optical Properties
Singly and doubly refractive with a negative optical sign; strong dichroism showing different hues when viewed from various angles; high refractive index ranging from 1.762 to 1.770; occasional asterism or chatoyancy in specific varieties
Hardness & Durability
Origin Region
Kashmir, Myanmar (Burma), Sri Lanka, Madagascar, Australia, and Montana (USA); formed in metamorphic and igneous environments
Hardness & Durability
Mohs hardness of 9, making it exceptionally durable, scratch-resistant, and ideal for daily jewelry wear with excellent toughness and high stability against heat and chemicals
Care & Maintenance
Safe to clean with warm soapy water, ultrasonic cleaners, and steam cleaners unless heavily fractured or inclusion-filled; store separately to avoid scratching softer gemstones; resistant to standard household chemicals
Rarity & Value
Varying from common to extremely rare depending on color saturation, clarity, size, and geographic origin; untreated stones with vivid saturation command high prices, while treatments like heat enhancement are very common and accepted
Special Characteristics
Notable for extreme hardness, high refractive index, and occasional color-changing properties or star asterism caused by microscopic rutile needle inclusions
Lore & History
Historically worn by royalty and clergy to symbolize wisdom, virtue, divine favor, and good fortune; in crystal healing, blue sapphire is traditionally associated with the third eye and throat chakras to enhance mental focus and spiritual clarity, though these are cultural beliefs rather than scientific claims