Diamonds with very little color are the most highly valued and are priced accordingly. A little color can diminish a diamond’s brilliance.
A fluorescence grade of strong or very strong can make a diamond with a near-colorless grade look even whiter yet in some instances give the diamond a slight hazy or oily appearance. Diamonds with a strong or very strong fluorescence are priced slightly lower than other diamonds.
For the purist, look for a colorless diamond with a grade of D-F and a fluorescence rating of faint, inert, none, or negligible.
For an excellent value in a diamond with no noticeable color to the unaided eye, look for a near-colorless grade of G-I, and a fluorescence grade of medium or strong blue.
Or, if you’d rather not compromise on color but would like to stay on budget, choose a diamond with a good cut, SI1–SI2 clarity, and consider going with a strong fluorescence. It will still be beautiful to the unaided eye and you may prefer the unique effect of a strong fluorescence.