IJ is for the diamond’s colour on the diamond classification scale, while I2-I3 stands for its clarity. Diamonds from IJ are almost colourless. Internal defects in diamonds with an I2-I3 classification are discernible at a 10x magnification and may be evident to the unaided eye.
The most expensive diamonds have a D colour grading and are colourless. The second-best colour tier for diamonds is almost colourless, and it is represented by an IJ rating. Color-rated S-Z low-grade diamonds are visibly yellow to the unaided eye.
The letter “I” denotes “inclusions,” or flaws within the diamond, in the ratings I2-I3. Internal defects including knots, cavities, and graining are frequent. The lowest grade of the six possible diamond clarity grading is I2-I3. FL created the top tier to be “flawless.”