Sapphire
Corundum var. Sapphire · Precious Gemstone
Crystal System
Trigonal; typically hexangular tabular or bipyramidal crystals, often massive in jewelry settings like this cluster.
Mineral Group
Oxides (Hematite group)
Chemical Formula
Al2O3 (with traces of Fe and Ti)
Formation Process
Metamorphic or Igneous; forms under high pressure and temperature in aluminum-rich environments like marble or basaltic rocks.
About This Crystal
The image shows a cluster of dark, forest-green to teal-blue round-cut stones. They appear translucent to opaque with a vitreous luster, set in a vintage silver-toned floral cluster mounting.
Physical Characteristics
Color: Dark Green/Teal; Streak: White; Fracture: Conchoidal to splintery; Density: 3.98-4.06; Luster: Vitreous to sub-adamantine.
Optical Properties
Refractive Index: 1.76-1.77; Double refraction (Birefringence 0.008); Strong pleochroism (often showing blue and green from different angles).
Hardness & Durability
Origin Region
Thailand, Australia, Sri Lanka, and Madagascar; typically found in metamorphic rocks or alluvial deposits.
Hardness & Durability
Mohs Hardness: 9; Extremely durable and tough, second only to diamond, making it suitable for high-wear jewelry.
Care & Maintenance
Generally safe for ultrasonic and steam cleaning unless heavily fractured. Clean with warm soapy water and soft brush. Store separately to avoid scratching other gems.
Rarity & Value
Common to Uncommon; these specific dark green-teal sapphires (often called 'Parti' or 'Australian type') are more affordable than cornflower blue, usually ranging from $50-$300 per carat depending on clarity.
Special Characteristics
Possible color-zoning visible in the central stone; high thermal conductivity; lacks fluorescence in dark green iron-rich varieties.
Lore & History
Historically known as the 'Stone of Wisdom'. In traditional lore, green sapphires are associated with the heart chakra and are said to bring loyalty, integrity, and trust.