Mặc dù hầu hết mọi người tin rằng kim cương trong suốt hoặc không màu, phần lớn kim cương có màu vàng, màu nâu, và màu đen. Hầu hết những viên kim cương đó đều được sử dụng cho mục đích công nghiệp, (mũi khoan, lưỡi cưa, vân vân.) Màu kim cương hiếm nhất là màu trắng (hoặc không màu). It is very common to find slightly brown or yellow diamonds in today’s jewellery. The whiter the diamond is, the more valuable the stone is.
Diamonds are graded for color face down, against a white background. The diamond is then assigned a letter grade. Most diamonds used for jewellery purposes fall into the Near Colorless Category – G to J. The Gemological Institute of America (G.I.A.) grades color alphabetically from D (totally colorless) nó là (màu vàng). For a diamond to be considered “colorless,” the G.I.A. requires that it be a D, E, or F.
Perhaps the most important factor to consider when selecting color is the type of setting you plan on using. If you plan on mounting the stone on a platinum or white gold setting, consider a diamond in the D-G range. Yellow gold will be much more forgiving to a less than colorless stone, but regardless of the setting, the diamond will start to appear yellow if the color grade is lower than about J.