Tuesday, February 8, 2011

Diamond Cut Grades

If you are shopping for a diamond undoubtedly you have heard about diamond cut grades and how important they are in your selection process.  While it is true that the cut is important, it is just a little more complex that reading one cut report and knowing the whole picture about whether that particular gem is, or is not well cut. Let me try to explain.


The cut of a diamond refers actually to the measured proportions of a stone regarding its diameter, the diameter of the table, the total depth, percentage of that depth above and below the girdle, the angle of the gem from the girdle to the table and the angle toward the pavilion.


That’s a lot of angles and measurements to consider, and in fact all of the grading labs have developed their own proprietary set of formulas to assess these measurements and tell the grader if the gem, in the opinion of their formula, is well cut, or not well cut.  The important point here, that grade is based on their formula.   Strange how a different and equally reputable grading lab just might give that same stone a completely different cut grade.  No two labs use the same criteria.  If this sounds a little subjective, you are correct, it is all highly subjective, but within some very limited cutting bounds.


You can be assured that any stone that is graded a top cut, from any lab or grading service, is in fact going to be brilliant in appearance.  That’s the overall objective, and each lab can achieve the same goal and yet not agree with one another.


In face, what you really want to learn for this cut grade report is whether the gem is brilliant or not.  Sounds simple, and in fact if you can personally observe two stones side-by side you can tell for yourself if one is more brilliant that the other. 


I strongly suspect that over the next few years we will very likely see all these cut formulas be replaced with a completely new grading system which will measure brilliance directly.  When that happens the cut will not be important, as the actual brilliance will be what is graded.


The point to remember is that a well cut stone is brilliant, and even a stone that is not in that top cutting grade may be just as brilliant to your eye as a stone that is not that labs top grade.  This can happen when a gem’s measurements misses one of the lab’s formula’s criteria by .01mm in depth, causing it to miss the top grading criteria.  However, that .01mm but inconsequential to what you eye can actually see.


You should always look at the gem instead of the gems measurements.  Just like you can’t tell from a person’s height, weight, arm and leg length, breast and hip size if that individual should be graded beautiful, the diamond cut grade may not tell you the complete story about if a stone is brilliant. 


Look at the gem, not the paperwork.  This is always the best way to tell you if the stone lights your personal wick and makes you smile, so that you can make her smile too.