Like their gemstone cousin the sapphire, rubies are just a variety of corundum, or aluminum oxide. Where sapphire gets its blue tint mainly from iron, rubies get their pink to blood-red hue from ...

Magmas similar in composition worldwide are known for their abundance of sapphire. Why this extremely rare variant of corundum is frequently found in this type of volcanic deposit has been a ...

This gem is a 350-carat blue sapphire from the corundum family ... and Jewellery Authority does not provide appraisal values for rough stones. This has made it difficult to export the stone.