The most important factor in the value of a ruby is color. A fine ruby 's intensity of color is like a glowing coal. It is no wonder that ancient civilizations ascribed magical powers to the fires that burned perpetually inside these brilliant gems. After color, the other factors which effect the value of a ruby are clarity, cut and size. Rubies often Rubies often have a velvety texture that makes them less transparent but which actually enhances the impact of the rich red color.
Skillful cutting can add sparkle and life to a ruby .
The shape should also be symmetrical with no nicks or scratches in the polish. Rubies may also be faceted into other shapes, including square, round, emerald cut, pear shape or marquis cut, but these fancy shapes are difficult to find in sizes above a carat. Like other gemstones, rubies are sold per carat, a unit of weight equal to one-fifth of a gram. Larger rubies , because they are more rare, will cost more per carat than smaller stones of the same quality. Rubies to today are even more rare and valuable than the best colorless diamonds.