Chrysoberyl

The mineral or gemstone chrysoberyl is an
aluminate of beryllium with the formula
BeAl2O4. The name chrysoberyl is derived from
the Greek words chrysos and beryllos, meaning
"a gold-white spar". Chrysoberyl is the
third-hardest frequently encountered
natural gemstone and lies at 8.5 on the Mohs
scale of mineral hardness, between corundum (9)
and topaz (8).