Yellow sapphire represents the positive powers of Jupiter in Vedic astrology, widely known as Pushparagam and Pukraj.yellow is sunshine and one of the warm colors. The color is symbolic of cheerfulness and used to welcome loved ones at home. In many civilizations across the world yellow represents courage, trade and peace.

IN INDIA YELLOW SAPPHIRE IS OFTEN MISTAKEN FOR YELLOW TOPAZ.YELLOW TOPAZ AND YELLOW SAPPHIRE ARE TWO DIFFERENT STONES.

Chemical composition
Yellow sapphire is made of Aluminum Oxide and Iron

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
Sri Lanka

Other sources
Sri Lanka

Other sources
Burma

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.

Irradiation It involves bombarding a stone with electromagnetic radiation( x rays or gamma rays)or subatomic particles (neutrons or electrons) to change the color. Color is not stable and fades when gem is exposed to heat or light.

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   :    May cause fractures

Light   :    Fracture filling may dry out or alter under intense light

Chemicals   :    Fracture filling may be affected by any type of chemicals, emerald itself is resistance to all acids except hydrofluoric

Synthetics
Synthetics Yellow Sapphire are readily available in the market.

Yellow Sapphire are grown in laboratory by FLAME FUSION AND FLUX METHODS.

THE ONLY WAY TO SEPRATE NATURAL YELLOW SAPPHIRE FROM LAB GROWN YELLOW 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    :    Water safe, but strong detergents should be avoided.

Please see the Checklist on how to buy gemstones scientifically