The price of diamonds can vary greatly depending on size, cut, color, and other factors, including whether they have a history. But because of the rarity of blue boron diamonds, they often fetch more money than gems of similar quality.
On a submicro scale, pure diamond is billions of billions of carbon atoms bonded to one another. If you shrunk yourself down and stood inside the diamond, you'd see nothing but carbon in a perfect pattern in every direction.
The body tends to treat elements in the same column of the periodic table as equivalents.