I saw Mara''s 1.6 carat J RB in platinum in person and LOOOOOVED it. I think it was gorgeous.
Of course, the extent to which the color will be noticeable depends on the cut. IMO, cut is WAY more important than color. And of course, one J won''t necessarily look like the next J; it really depends on the particular stone and where the cert. is from (some certs are more strict than others...i.e. a GIA J might be called an I or maybe even an H by a cert with less strict standards.)
As the wise consumer cadre has offered, it''s about shape - and especially about cut.
The shape of a diamond influences the amount of color people may see in it. A round brilliant is the most efficient shape for returning light and shows less apparent color than another shape like a princess, an emerald or asscher. As for cut - diamonds are graded in the face-down position, viewed from the side. This is because superior light return in a diamond can ‘mask’ color. Extremely well-cut diamonds may appear more colorless in the face-up position than the grade they received at the lab due to superior light return. For instance, a diamond that was graded H in the side position can ‘face-up’ like a G or an F, but only if it was cut extremely well.
I would also add that the lab that graded the diamond is very important. Some labs are stricter than others. The AGS and GIA are considered very strong labs in ''these parts.''