A gem which in value and hardness ranks next to the diamond; is dichroic, of greater specific gravity than any other gem, and belongs to the hexagonal system of crystals; is a pellucid, ruddy-tinted stone, and, like the sapphire, a variety of corundum, also found (but rarely) in violet, pink, and purple tints; the finest specimens come from Upper Burmah; these are the true Oriental rubies, and when above 5 carats exceed in value, weight for weight, diamonds; the Spinel ruby is the commoner jeweller's stone; is of much less value, specific gravity and hardness, non-dichroic, and forms a cubical crystal.