Rocks loafing about on the surface of Mars have been harboring secrets about the red planet's mysterious past.

Mars expert Roger Wiens and his team, including the rover Perseverance, discovered fascinating rocks incorporating kaolinite ...

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 ...