Blue Sapphire
In standardized color terms. blue sapphire ranges from very light to very dark violetish blue to greenish blue.The most highly valued sapphires are velvety blue to violetish blue, in medium to medium dark tones.
It’s estimated that 95% of blue sapphire are heated or lattice diffused to improve color and clarity Source (G.I.A.).
Untreated premium quality sapphires–a tiny percentage of the sapphire market– make up the most exclusive and costly market sector.
Chemical composition
Blue Sapphire is made of Aluminum Oxide, Iron and Titanium
Species Corundum
Refractive Index 1.762-1.770 (+0.009/-0.005)
Specific gravity 4.00 (+ 0.10 /-0.05)
Melting point 2050 C (Approx)
Best source
Kashmir (India)
Other sources
Burma
Sri Lanka
Australia
Madagascar
Nigeria
United States
Heat Treatment Heating to a very high temperature for the purpose of changing its appearance.
Surface diffusion Heating at a very temperature in presence of coloring agents for allowing chemicals to penetrate in the stone.
Fracture filling Stones are filled with epoxy resin or glass OR lead glass to conceal the fractures.
Any treatment done on the stones damages its internal structure of the gemstones.
Hardness & Toughness
Hardness (resistance to scratching) 9 on the Mohs scale
Toughness (resistance to breaking and chipping) Usually excellent but large fractures can lessen the durability
Stability (Resistance to Heat and Chemicals)
Heat Heat can cause change in color or clarity, it can also damage fracture filling
Light Fracture filling may dry out or alter under intense light
Chemicals Can harm the fillings in fracture filled stones
Synthetics
Blue Sapphire synthetics are readily available in the market.
Blue Sapphire is made from flame fusion, flux, hydrothermal, floating zone many process in the market
THE ONLY WAY TO SEPRATE NATURAL SAPPHIRE FROM LAB GROWN SAPPHIRE IS THROUGH INCLUSION(MAGNIFICATION)
Care and cleaning
Ultrasonic cleaning Usually safe, but not for fracture filled stones.
Steam cleaning Usually safe, but not for fracture filled stones.
Warm soapy water Safe, but strong detergents should be avoided.
Please see the Checklist on how to buy gemstones scientifically
