Commercially known as topaz. All kinds of yellow gem-grade corundum. The color ranges from light yellow to light yellow, golden yellow, honey yellow and light brown yellow, with golden yellow being the best. Yellow is usually associated with the presence of iron oxide. Except topaz, the pale yellow color of sapphire is not common in other gems. The world's largest natural yellow sapphire is produced in Sri Lanka, weighing 46.5 carats, golden yellow, oval cut, pure inside and strong fire resistance.