The most common kind of crystalline alumina, α-aluminium oxide, is named corundum. When trace things make it appear crimson it is named ruby, but all other colorations drop beneath the designation sapphire. Corundum incorporates a trigonal Bravais lattice with a space group of R-3c (range 167 within the Global Tables). https://ericy741gik1.goabroadblog.com/profile