Prices of Blue sapphire depends on its characteristics - Natural or glass filled. Both heated and unheated are called natural but see how unheated sapphire changes the color and clarity during heating process. [Blocked Image: http://www.navneetgems.com/files/Blue%20Sapphire_0.jpg]
Most famous oval shaped Marbella' topaz weighs around 8,225-carats and known for its perfect color and cut, although 31,000 carats 'El Dorado' topaz is highest in weight.