Padparadscha sapphires are those sapphires that have a particular mix of orange and pink.

It is called Padmaraga in Sri Lanka, but around the world it is more commonly known as Padparadscha sapphire. The name Padmaraga is derived from the Sanskrit, meaning lotus (Padma) colour (Raga), signifying the vibrant mix of orange and pink tones reflected by the gemstone. 

Mineral Padparascha/King Sapphire
Chemistry Al2O3
Refractive Index 1.762 to 1.770
Birefringence 0.008 to 0.010
Specific Gravity  4.00
Mohs Hardness 9