In late April, I traveled to the Gemological Institute of America in Carlsbad, California to complete an intensive five-day Diamond Grading Lab as part of my journey toward becoming a Graduate Gemologist.
Here’s how the week unfolded.
Monday
Arrive and pick out a spot in the lab, furnished with a microscope and a pack of tools.
Review the 4Cs: carat, cut, clarity, color.
Learn to use my non-dominant hand to hold the tweezers and pick up the diamond, since you need your dominant hand free for taking notes and mapping inclusions and blemishes while you look at the diamond through the microscope.
Practice giving first-impression clarity grades to diamonds. I’m encouraged to trust my gut; one instructor says, “Think long, think wrong,” and it tends to be true for me.
Tuesday
Learn how to systematically examine a diamond in order to appropriately map all clarity characteristics to identify the clarity, support the clarity grade, identify the diamond (inclusions are like birthmarks!), and document the diamond’s condition at the time of grading.
Mapping a diamond’s clarity characteristics looks a lot like creating a treasure map, with specific meaning assigned to each symbol, abbreviation, and pen color.
Wednesday
Wednesday is all about precision.
We learn the cut quality factors that contribute to a round brilliant-cut diamond’s cut grade. This involves mathematical formulas and grading charts used to determine whether a diamond’s cut is Excellent, Very Good, Good, Fair, or Poor.
There are more than 8.5 million possible proportion combinations in a round brilliant-cut diamond. Fortunately, decades of research into ideal proportions have made the process more manageable by allowing us to plug measurements into standardized formulas.
We also learn how to color grade diamonds, first on their own and then by comparing them to master stones.
Next comes fluorescence. Some diamonds fluoresce—usually emitting a bluish glow, though occasionally yellow or orange—when exposed to long-wave ultraviolet light from sources like the sun. Only about 25-35% of diamonds fluoresce to some degree. While fluorescence is not part of a diamond’s grade, it is an important identifying characteristic.
Toward the end of the day, we complete a timed grading exercise. We’re given one hour to fully grade a diamond while the instructor cues us through each stage of the process. This is in preparation for Friday’s final, where we’ll have two hours to completely grade two diamonds on our own.
Thursday
Thursday is dedicated entirely to practice.
I begin with clarity first-impressions and color grading drills, quickly assessing piles of diamonds and checking my results afterward. If I’m correct, I move on. If not, I spend more time analyzing where I went wrong.
After that, I time myself grading two diamonds from start to finish. This is when I discover that my biggest weakness is taking tiny measurements—especially crown angles—so I spend the rest of the day practicing those.
Friday
It’s final exam day, and despite my successes throughout the week, I am a bundle of nerves.
My hands shake as I place the pointer probe against the diamonds assigned to me for the final. I take a few deep breaths, stretch my fingers, and power through.
I finish with about 20 minutes remaining and decide to head to lunch. I could go back and check my work again, but: “Think long, think wrong.”
Over lunch, my classmates and I swap stories about our diamonds (“The cavities!” “The twinning wisps!”) and talk about how we’ll celebrate passing.
And we all do.
The classroom erupts in applause, laughter, and sighs of relief when we learn that everyone passed the final.
Because I completed the classroom portion of Diamonds & Diamond Grading last year, I leave Carlsbad officially a GIA Diamonds Graduate!
