The commonest method of crystalline alumina, α-aluminium oxide, is known as corundum. When trace things make it look crimson it is named ruby, but all other colorations fall beneath the designation sapphire. Corundum features a trigonal Bravais lattice with an area team of R-3c (quantity 167 during the Worldwide Tables). https://aaronc962jlm2.wikimillions.com/user