The corindon-harmophane of nauy, corindon adamantin of Brongniart, the korund of Werner, and the adamantine spar of Kirwan. It is octahedral, rhomboidal or prismatic.

The earth alumina, as found native in a crystalline state, including sapphire, which is the fine blue variety; the oriental ruby, or red sapphire; the oriental amethyst, or purple sapphire; and adamantine spar, the hair-brown variety. It is the hardest substance found native, next to the diamond.

of Corundum