Aluminum oxide (Al 2 O 3), also known as alumina, corundum, sapphire, or ruby, is one of the best insulators used in a wide range of applications: in electronic components, as a support material ...

Like their gemstone cousin the sapphire, rubies are just a variety of corundum, or aluminum oxide ... was rewarded with a large, deep pink ruby. This looks like a fun, quick little project ...