Crystal field theory makes predictions about how a transition metal ion’s structure is affected by the other atoms surrounding it. Rubies are mainly made up of the mineral corundum, which is ...

corundum, anorthite and biotite. A crystallo-chemical enigma, it is one of the few rock-forming minerals with unknown crystal structure.

More than 4,000 naturally occurring minerals—inorganic solids that have a characteristic chemical composition and specific crystal structure ... of a mineral called corundum, comprised of ...

Aluminum oxide (Al 2 O 3), also known as alumina, corundum ... On the surface, however, the structure deviates from that inside the crystal. The strongly insulating nature of alumina has hindered ...