Where sapphire gets its blue tint mainly from iron, rubies get their pink to blood-red hue from chromium. So [NightHawkInLight]’s recipe starts with aluminum oxide grit-blasting powder and ...

In ruby - which is aluminium oxide with a few parts per thousand of the aluminium ions are replaced by chromium(III) ions - the chromium atoms are surrounded by six oxygen atoms. This means that the ...

chromium, and aluminum. And instead of a traditional structure, they intersperse molecules of oxides, which combine (in this case) metals and oxygen. Finally, the oxide dispersion strengthened ...