Imagine a glass window that’s tough like armor, a camera lens that doesn’t get scratched in a sand storm, or a smart phone that doesn’t break when dropped. Except it’s not glass, it’s a special ...
Long considered a kind of poor man’s ruby, the gemstone has come into its own. By Kathleen Beckett Pity the poor spinel. The gemstone that many people have never heard of has been saddled for ...
Spinel, MgAl 2 O 4 (download cif), is a rare gemstone that was used to imitate rubies. The structure has face-centered cubic symmetry, and is a little heavy to understand. The general formula is AB 2 ...