The "sparkel" or "brilliance" of a diamond is strictly a function of how the diamond is cut. By "cut", we mean the actual proportions between the diamonds "table"-"girdle" and "culet". When light enters a diamond through the table, it bounces around the facets, and if cut proportionatly, the light will be reflected back out of the table. The actual term for this is scintilation. The only 2 grading reports that are really thought credible in the jewelry industry are GIA and AGS. Other grading firms such as EGL or IGI have looser grading standards. A diamond house will use EGL or IGI to get a higher grading report for tha diamond, as the better the report the more they can charge. Buying on line is a BIG mistake, as often times the diamonds do not actually match the diamond you are being sold AND you must pay up front! Go to a local independently owned jeweler that is AGS certified , or one that will only offer a GIA or AGS grading report for their diamonds AND if you are still skeptical, understand the return policy and then take the diamond to an independent appraiser with GIA certification for an outside appraisal. Hope this helps!
