The most favored variety of corundum in existence, sapphire comes in different colors ranging from blue to orange. The deep blue color is the most popular one, and it will probably stay that way. One reason is that the deep color masks almost any inclusion present in the stone, which is hard to get in, say, a 1 ct blue diamond ring. The clarity or natural blue sapphires can vary a great deal, but most stones are good at hiding imperfections present within them.
Another form of corundum, ruby contains minute amounts of chromium, which give it different intensities of red color ranging from deep pink to blood red. The price of the ruby is based on how intense the color is which means the deeper reds are invariably more expensive. Many celebrities frequently sport ruby engagement rings in public, so you will not be in bad company if you choose this stone over a diamond.