The most common type of crystalline alumina, α-aluminium oxide, is known as corundum. When trace features make it show up pink it is known as ruby, but all other colorations fall under the designation sapphire. Corundum provides a trigonal Bravais lattice with a space group of R-3c (amount 167 while https://lanthanumcarbonate08753.dailyhitblog.com/40277334/碳酸-secrets