List of rubies by size

A ruby is a pink to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide).

Ruby is one of the traditional cardinal gems, together with amethyst, sapphire, emerald, and diamond.

The quality of a ruby is determined by its color, cut, and clarity, which, along with carat weight, affect its value.

The brightest and most valuable shade of red called blood-red or pigeon blood, commands a large premium over other rubies of similar quality.

After color follows clarity: similar to diamonds, a clear stone will command a premium, but a ruby without any needle-like rutile inclusions may indicate that the stone has been treated.