Zale’s Tales: Diamond Cutting
I started learning about diamonds and diamond cutting as a teenager, working in the old Zale New York office at 450 W 33rd St. Because Zale was a DTC Sightholder, from the late 1950s to the mid-1980s, we were fully engaged as diamond manufacturers.
My Early Diamond Cutting Days
In the New York office, we received the rough and then determined how best to take each stone in order to maximize its value. Because we were mostly cutting rounds from octahedral and dodecahedral rough, we would saw the goods in our factory at 450 West, where we had about 120 sawing benches. That is how I began my diamond education — over the summer when I was 17.
In the days before Galaxy machines, we would assess each rough stone by eye and then mark it for either sawing or cleaving. To mark the rough, we would touch a fine point dip-pen to a metal coil that had been dipped in a small bottle of India ink, and then draw a line, as fine as possible, for the Sawyer. Learning how to draw the fine line took a while, and my first stones seemed to be covered in ink! But, in time, I could draw a line as fine as a laser.
The Blocker first cuts the four top corners and the four bottom corners of the diamond. Next, it goes to the Girdler for bruting in order to make it round. Then, it goes back to the Blocker, who would make the stone in 8/8 cut: eight top facets (four top corners and four bezels) and eight bottom facets (four bottom corners and four pavilions). If you compare diamond cutting to building a house, blocking is akin to the framing.
Most of the rough would be sawn, but some were bolles (the Flemish word for ball, a rough stone from which you would only get one polished diamond). On those, we would mark the table for the Blocker.
Lastly, the diamond is finished by the Brillianteer, who applies the stars, top halves and bottom halves (the final painting and wiring on your new house).
Tricks of the Trade
I learned about rough and diamond manufacturing from an old-school expert named Howard “Rocky” Rothwax. Howie was a piece of work, but he really knew rough diamonds. He was an expert’s expert. He was also a cousin of the famous NYC Judge, Harold Rothwax, a.k.a. “The Time Machine” because of the long sentences he would hand down. But I digress.
The same bench that would saw a rough diamond, using diamond powder mixed with oil applied to a copper blade, would also put the groove in a blocked out heart shape. You just needed to replace the thin copper blade with a wedge-shaped blade. Our factory in San Juan, PR, would block the diamonds after we sawed them in NY, and then send the hearts back to us for grooves. Then, we would send them back to San Juan for brillianteering.
That summer I grooved a lot of hearts in addition to sawing a lot of rough. So I’ve always considered myself a groove aficionado. Yeah, that and $2.75 will get me a ride on the subway.
The Graff Venus Diamond
It was exciting to see the recent announcement that Graff had cut the world’s largest D flawless heart shape diamond. 118.78 carats! It’s a beautiful, historic diamond! Now, far be it from me to second-guess Graff, but if you ask me…I would have gone a hair deeper on the groove. I’m just sayin’.
What makes the Graff Venus especially cool is that it is also a Type IIA diamond, meaning it is virtually devoid of nitrogen and nearly all impurities. Type IIA diamonds are rare. They make up about 2% of all mined diamonds. Sometimes they’re called Golcondas, referring to the original diamond finds in India, which yielded stones of exceptional color and clarity. Read more on the Golconda mines here.
I recall a magnificent type IIA rough of a little over 40 carats that I saw in the late 90s. It was cut to about a 28 carat D, FL briolette and cut in a style which so perfectly mimicked 19th-century faceting arrangements that not even experts could discern that it was a new diamond from South Africa and not an original Golconda.
Interestingly, at this point in time, type II diamonds also make up 100% of all lab-grown diamonds. So it’s wild to consider that the Graff Venus would not pass the basic screening that jewelers find necessary to use in order to ensure sure they aren’t confronting a non-disclosed lab-grown diamond. In fact, it’s downright ironic that the most beautiful diamonds are so similar to lab-grown diamonds in their appearance. So we all need to remain vigilant and screen for lab-grown diamonds, and when we do sell a lab-grown diamond— disclose, disclose, disclose! And as Phil Esterhaus would say, let’s be careful out there.
Maybe next time I’ll write about why you would never ask Howie Rothwax to bring you a cup of coffee from the break room. You’ll just have to remain in suspense until then.
A conversation with Howie Rothwax:
Me: Asking a technical diamond question
Howie: Responding with a technical answer
Me: Got it. Thanks.
Howie: Do you follow what I’m saying?
Me: Yes, thanks
Howie: But do you follow me?
Howie: But are you following me?
Me: Yes, yes. I’m following you.
Howie: Stop following me