These were shown by Becquerel to have the cleavage of corundum, and contained small cavities lined with crystals of ruby. Gaudin concluded that alumina could not exist in the vitreous state ...

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 ...

Rubies are formed of a mineral called corundum, comprised of aluminum oxide. The red color is caused by traces of chromium. Corundum also forms sapphire in many colors, which generally come from ...

Medium and Commercial Quality), no Corundum Rough Ruby (Higher, Medium and Commercial Quality), no Corundum Rough Ruby (Higher, Medium and Commercial Quality), no 'Low Ruby' 1 or Corundum Rough ...

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 ...