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 ...

The symbolism of spinel depends on its color. For instance, red spinel is associated with passion and devotion. Others believed red spinel could stop anger and bring harmony. It was also thought ...