What is a diamond? A fine diamond with desired fire and clarity is 100 percent pure carbon. Only one atom of nitrogen in a hundred thousand atoms of carbon can give off a yellowish tinge to the stone making it less valuable. Most diamonds are so small that the off color is barely noticeable. A truly flawless diamond is rare, about 1 in 800.
It was not until diamonds were faceted that they were considered more valuable then rubies and emeralds. Diamonds are the hardest of all natural substances and is the only gemstone that can be used as a cutting tool, making it more useful then any other gemstone.