by oldminer » Dec 24, 2012 The HCA is based on the following scale: "0-2 Excellent, 2-4 Very Good, 4-6 Good, 6-8 Fair, and 8-10 Poor" I am often asked hairsplitting questions such as is a 1.0HCA going to be "better" than a 1.2HCA?" In all truth I likely cannot see the difference with my naked eyes, but that does not mean there is no absolute difference measureable in some technical way. I also get asked about a stone falling close to the 2.0HCA reading and how it would compare to a 0.7HCA stone. Again, possibly I might see the difference, but both would rate "Excellent" under the HCA strategy of grading categories. Would you all consider such diamonds both equally excellent or do you grasp the concept of a range of diamonds slightly different from one another all being in the excellent pool? What is the highest (worst) numerical score for an AGS000 anyone ever saw? What is the highest numerical score for a GIAXXX anyone has ever seen? Such questions are often being asked and I truthfully don't have any exact experience with the limits of the HCA results. Can there be a diamond AGS000or GIAXXX with an HCA above 2.0? 2.1, 2.2--3.0 Where is the limit?