Blue Sapphire (Neelam)

Blue sapphire reflects the sky’s every shade, from blazing afternoon to velvety midnight. It symbolizes nobility, truth, sincerity and faithfulness.

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 colour 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 Aluminium 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

Treatments

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.