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 ...

An exhibition showcases the sophisticated cultural language developed in the Indian subcontinent from around 1560 to 1660 across the reign of three emperors.

The Zurich-based gemmologist says it’s fascinating to see people’s outwardly expressed or more guarded personalities match with a charismatic morganite, a calming lavender spinel, or a joyful ...