The commonest kind of crystalline alumina, α-aluminium oxide, is referred to as corundum. When trace features ensure it is seem pink it is named ruby, but all other colorations fall under the designation sapphire. Corundum features a trigonal Bravais lattice with an area team of R-3c (selection 167 during the https://metallography54209.digitollblog.com/34674806/how-aluminum-oxide-can-save-you-time-stress-and-money