These two chimera African violets, (Concord), were clones from the same parent plant. The flowers are different. You may perceive the difference in the blooms (above and below) subtle or not but there is a difference. I consider the top one unacceptable and frankly destined to the compost heap. That is not atypical when some of my chimeras’s just don’t look right to discard them. A very subjective approach I know, but I find it frustrating to see Concords as well as other cultivars being offered with margins that are obviously much thinner then what the person that hybridize it originally offered. I have seen this specifically on occasion with concord flowers (as illustrated above) with smaller white margins, the purple is not necessarily even in coloration and it appears that there are some white specks in the purple. Also in the white portion there is a purple hue. Finally the edges of the petals appear thicker.
Below is (what I consider a proper Concord bloom) the image has a larger white areas, the white is pure white with no purple hue, the bloom is larger and the purple coloration is even with no tiny white specks. Also the edges of the petals are not thicker then the rest of the petals. It is what a concord should be. The photographs were taken with some back lighting to help illustrate the points of the coloration.