Gems : Ruby

Ruby is the usual name for transparent red corundum, and is red or pink. Blue corundum, or any other colour, is usually called sapphire.
Very dark rubies appear black, and aren’t very attractive or desirable. The darkness is often caused by flaws, or ‘inclusions’. Equally, an extremely pale ruby would be colourless, and not particularly attractive or valuable. The most desirable rubies are generally those with an intense red colour, and plenty of sparkle and life. Skillful cutting usually helps with the latter.
One important factor when selecting a ruby is to ensure that it will not clash with your nail varnish or other clothing and accessories. This is a more important factor with ruby than with almost any other gemstone. Colourless diamonds, blue sapphires, and green emeralds hardly ever clash with other colours, but you need to be much more careful with reds and pinks.