Diamond is a naturally occurring pure carbon crystal that is exceptionally hard and durable compared to most gemstones. Gemstones are also mineral crystals that are cut and polished for use in jewelry. When assessing durability, diamond is unmatched due to its extreme hardness and stability against damage or deterioration. While most diamonds are colorless, colored diamonds can be found and are more rare and valuable. Gemstones also come in a variety of colors and some treatments are used to enhance their hues, though the effects may fade over time. The value of both diamonds and gemstones is determined by the four C's of cut, clarity, color, and carat weight, with rarer qualities increasing price.