Guest post by Dan Gillen
For as long as I can remember I have heard the Diamond Trade say ”Just hire more diamond graders” The truth is it’s not that easy and not the full remedy to the long turnaround time. Why do I know this? I know this because I had a career in a diamond lab.
First, let’s talk about the” Just hire more graders”. New graders are not available for the picking they have to be trained to diamond grade. Even those that come out of the GIA ‘s GG program do not know how to grade as a laboratory diamond grader. Back in the mid 80’s I along with others helped produce a formal training program. I spent almost three years training newly hired trainee diamond graders. I sat with no more than ten at a time but six to eight was more ideal. We spent three months, eight hours a day learning every aspect of grading. From microscope usage and louping ability to polish, symmetry, plotting, clarity assigning, girdle thickness, culet size and so on. The trainees graded diamonds that were submitted by clients and had already been graded by the regular graders, thus holding them up for return, for at least a week, unbeknownst to the client. After three of training the trainees that made it this far were now allowed to be within the lab population and were known as preliminary graders.
Back then when plotting was more manual, meaning pen and paper, some new preliminary graders could only finish 12-15 diamonds per day, and if you could do 20 you were considered to be above average. My last words to the new graders going into the lab was that it takes from three years or more before you have graded enough diamonds of various qualities before you have a chance at being a good to excellent grader. What that means is that at 2o stones a day for three years a grader will have graded almost 15,000 diamonds, but if they were only averaging 15 a day then it would take 4 years to get to 15,000 graded diamonds.
In addition to the lack of fire power a new grader brings to the lab they also create a burden to the secondary graders or the “Double Checkers” as they are known. These are the next level of experienced graders that check the Preliminary Graders work. The burden is due to mistakes and feedback required when checking new graders work, which in turn slows the Double checkers output. So, as you can see hiring new graders doesn’t actually speed the process up, it may actually slow things down, for awhile!
Keep in mind that the new graders do not do any color grading until they have mastered the Art of diamond grading, which as I said could take years.
That brings me to the other grading skill- D-Z color grading and this is where the turnaround time suffers the most.
Let’s create a theoretical diamond grading lab. Using the process and different levels of grading established at the largest lab available here is how the distribution of graders might be; 500- Preliminary Graders; these are the least experienced graders that do all the initial grading accept color on a submitted diamond. Let us assume that each one of these graders can complete 20 diamonds a day in an 8 hour day, 5 days a week. That means that they will finish 10,000 diamonds per day. That means 10,000 diamonds per day need to be checked by the next level of diamond grading experience which are the double checkers.
250- Double checkers; this is the amount of double checkers needed in order to check 10,000 preliminary graded diamonds per day as long as each double checker can do 40 per day. For simplicity sake let’s pretend that all 10,000 diamonds have agreement on polish, symmetry and clarity at this point,(this does not happen).
Quality Assurance Graders- to do 100% QA, the lab would need another 166 graders that are at a level of checking over the final results for polish, symmetry and clarity, at a rate of 60 per day.
At this point the lab requires between 900 and 1000 graders. Now let’s look at the backlog, all these stones need to be color graded. Not everyone in the lab is taught or even allowed to color grade and it is usually a task designated to double checkers and above. Regardless, the lab still needs these graders to spend some time color grading. Most graders that color grade do so for one hour a day and are given 50 diamonds to color grade at a time. This can be done as a team or split up as individuals but as a team is more efficient. It takes an hour to do 50 as a team. At that rate, 10,000 diamonds per day would need 25 individual D-Z diamond master sets for 50 color grading graders to sit at for 1 hour times 8 hours in a day. That would utilize 400 individual color graders. In reality a consistent team of color graders will agree on the same color about 80% of the time. That means for each set of 25 master sets every hour there will be 250 diamonds that are a split color grade and will need a third color grader to input a color grade. That will bring the total for the day of an additional 2000 diamonds that will need a third color grader. That means that we would need an additional another 40 color graders and an additional five master sets running 8 hours a day for split grades to be completed.
It takes months to find and complete a D-Z master color grading set at the level that an important grading lab would need. It can be done. But graders aren’t robots and fatigue sets in, absences, vacations etc. No one can keep this kind of pace up.
So back to my first sentence, Why not just hire more graders? Well, a lab can have thousands of diamond graders but they can only return per day the total amount that they can color grade and in my opinion it is well short of the above scenario. If such a large company would be more transparent to how diamonds flow through the lab and how many man hours it takes for each process we would understand that just hiring more graders will not make a difference with backlog.
This is not written to bad mouth the situation or any diamond grading company. It’s simply an explanation as to how things work and why more graders will not change turn around time
Dan Gillen is a Gemologist/Diamond Grading Expert at LJ West Diamonds