For your reference, here are the GIA color grades:

• D, E, F: Colorless (white)
• G, H, I, J: Nearly colorless
• K, L, M: Faintly yellow
• N, O, P, Q, R: Very light yellow
• S, T, U, V, W, X, Y, Z: Light yellow
• Z+: Fancy colors (such as the Hope Diamond, which is a deep violet)

A diamond's clarity depends on how clean, or free of imperfections, it is. There are two types of imperfections: Blemishes refer to chips, scratches, fractures, or polishing mistakes on the outside; inclusions refer to spots and cracks (also known as feathers) on the inside.