Corundum
Formula: Al2O3 From Alfredo Petrov: Above: About 20 1mm gem blue zoned sapphires from a placer deposit. Anamushi alluvials, Kashiba City, Nara Prefecture, Japan.
Formula: Al2O3 From Alfredo Petrov: Above: About 20 1mm gem blue zoned sapphires from a placer deposit. Anamushi alluvials, Kashiba City, Nara Prefecture, Japan.