Diamonds come in a variety of colours, some of them are highly prized (pinks, blues even yellow). The categories of the grades of the colourless diamonds are D-E-F are Colourless. G-H-I-J are Nearly Colourless. K-L-M are faintly tinted, usually yellow. S-T-U-V-W-X-Y-Z are tinted, usually yellow, may progress to brownish. H, I, J, K are the popular colours.