Diamond color refers to the hue and tint of a diamond, which can significantly affect its value. The Gemological Institute of America (GIA) grades diamonds on a scale from D (colorless) to Z (light yellow or brown). Colorless diamonds are the most sought after, as they allow maximum light reflection, enhancing their brilliance. The presence of color in a diamond is caused by various factors, including the diamond's chemical composition and the way it was formed. While some colors are considered rare and valuable, such as pink diamonds or blue diamonds, most diamonds fall within the D to Z range, where subtle differences can impact their overall appearance and price.