Most people think of a diamond as a beautiful gemstone used to make beautiful jewelry. But do you know what your diamond really is?
Technically, a diamond is an allotrope, or a form, of the element carbon (a diamond is actually carbon in its most concentrated form). Within a diamond, the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. This arrangement of carbon atoms essentially means that the diamond expands outward at the same rate in all directions during its initial growth.
Because of its structure, which is extremely rigid, a diamond can be contaminated by very few impurities, such as the elements boron or nitrogen. Combined with its tendency to be transparent, this results in the colorless, clear appearance of most diamonds. Blue diamonds come from boron impurities, yellow diamonds from nitrogen impurities, brown diamonds from lattice defects, and green diamonds from radiation exposure.
A diamond is the hardest naturally occurring material on Earth and is much rarer than gold. About 175,000 tons of gold have been mined in all of human history, while only around 500 tons of diamonds have been mined in the same amount of time.