The 4Cs: Clarity
Early on in their lives, every gemstone was once a loose packing of sediment. In the case of diamonds, that's pure carbon. As the carbon is packed under heat and pressure the black carbon crystalizes and clarifies. The longer, hotter, and harder the carbon condenses, the more clear it becomes. For this reason, diamonds range in color and clarity. When there are bits of carbon or other mineral types, which are called inclusions, the clarity drops. On one end of the spectrum you have flawless, crystal clear diamonds (which are the most expensive) and on the other heavily included, “salt & pepper” or black diamonds. That said, included or not, a diamond is a diamond and will have the same durability and chemical make-up.