Multiple choice

Ruby and sapphire are oxides of

  1. copper

  2. tin

  3. iron

  4. aluminium
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Ruby and sapphire are both varieties of the mineral corundum, which is crystalline aluminum oxide (Al2O3). The red color of ruby comes from trace chromium impurities, while sapphire's blue color is caused by iron and titanium impurities. Though they appear different, both share the same chemical composition.

Keep practicing — related questions