Sapphires and Rubies - The Subduction Zone

A lot of the common names for gems are based upon their look. Not necessarily there their mineral structure. They're all corunm crundum also can have like, an opaque, brownish, kind of likelosica rock,. Yat the crystalline, translucent ones. If there's iron, trace iron in it, then it's red, like a ruby. And if there's trace either titanium or chrome in there, then it'm a chromium. Then it's blue. Actually, sapphires are rubies are corundum, that's red. But they're mostly not, is true. Idon't refer to them as like, green sapphire