#JOTW A 5ct OEC Finds a New Home and Some TLC

[prs]

When we met with the new cutter it became quickly apparent he had learned his trade after computers and Sarine scanners revolutionized diamond cutting. By revolutionized I mean the new technology allowed master craftsmen to achieve much greater precision, and make much more informed cutting decisions. He was very proud of his Sarine and its high degree of accuracy, he also told us, without being asked, that it had just recently had one of its regularly scheduled calibration checks. He showed us how he could display numerous different views of the diamond on his computer screen. I knew then we had found the right guy. He wouldn’t be trying to cut the Lower halves by eye, but rather using the highly accurate data from his Sarine to help make his cutting decisions. We gave him our diamond to scan and here is a copy of the result.



To our surprise the Lowers measured fairly close to the last scan from our old cutter (more on this later), and very near to plan. David had said he could see the flower petal pattern, but his eyes are much younger and sharper than ours. Neither DW or I could see it with the naked eye. I could see it with a loupe, but DW wasn’t interested in carrying a loupe around all day. She wanted to be able to see the pattern with her own eyes from normal viewing distance!

DW and I had previously discussed this possibility. She had initially wanted the “Old European’ cert, but to get a visible flower pattern she was perfectly OK with a “Circular Brilliant” cert. We then discussed this with David and all agreed the next step would likely be to further increase the length of the Lowers. Our new cutter had also never heard of the flower petal pattern, but said increasing the Lowers to around 65% would be no problem. We gave the OK for him to proceed with Stage four, and that is exactly what he did. A couple of days later we had our diamond back with a beautiful, visible flower petal pattern. Our new cutter definitely proved he had the technology and skill to accurately cut Lower half facets. Here’s a copy of one of the facet diagrams he made for us from a scan of the diamond after stage four was complete. It shows the length of each Lower half together with the cut angles of each of the 16 lowers



The culet is around 0.5mm but look how precise the octagon shape appears on the scan. Amy took a photo of the unset diamond before she sent it to GIA, and the culet exactly matches the scan. A tribute to the accuracy of the Sarine.



Needless to say we were very anxious to get the new weight, and to our great delight it weighed in at 5.05ct. We only lost one point during stage four, what a happy ending!!! Our rehab had been a huge success and the Champagne definitely flowed that night!!!

 

[Matata]

Fabulous

 

[prs]

Fabulous

Thank you!

 

[prs]

We all know when it comes to diamond inclusions there is loupe clean and eye clean. We learned from our rehab adventure that for the flower petal pattern there is also loupe visible and eye visible. We discovered that looking at a facet pattern on a computer screen is a whole lot different from looking at it in real life. Going back to my favorite AVR photo



In real life this diamond measures 7.84 mm, but on the screen of my laptop it measures almost 5 ½ inches, 135mm. So it’s like looking at it under a 20X loupe. After stage 3 our flower petal pattern, with its 61% Lowers, was almost identical to this photo, but in real life neither DW or I could see the pattern. At our age our eyes are certainly not as sharp as they used to be, and no doubt many younger ladies here would be delighted with this diamond.

FWIW Victor Canera cuts his CERs with 66% Lowers, and that’s almost identical to our OEC after stage four. Here’s a facet diagram I put together comparing the look of different Lower half lengths. If you prefer the pin wheel pattern the diamond on the left is yours, but for flower petal lovers its difficult to chose between the middle and right hand diamonds.



Here’s how they look reduced down closer to life size; the pattern on the right becomes more easily visible.



So the first lesson we learned from our recut was to make sure our preferred facet pattern would be visible to the naked eye, and in particular DW’s naked eye!! This mistake did cause us a little temporary heartburn, but fortunately we were able to correct it for relatively little monetary cost.

 

[prs]

@prs - never have I ever understood the cut of an OEC more. And on the first read through too! Awesome descriptions with wonderful diagrams. I feel like this needs to be pulled out into its own thread or added to some sort of main OEC knowledge thread or something.

Just for you, another quick word on Lower Half facet lengths. You may recall DW’s OEC ended up at 65% because she wanted a visible flower petal pattern. I didn’t know it at the time, but it may well be these longer lowers also improved the light performance of her diamond. For sure her diamond becomes a blindingly white fireball in any direct light.

The American Henry Morse in the 1860s is acknowledged to be the first cutter in the world to cut diamonds for beauty rather than weight. He is also credited with being the first to lengthen Lower halves from around 30% to 60%. It’s not known exactly what length Lowers Marcel Tolkowsky used in his famous 1919 publication, but he too is believed to have used around 60%. Since that time, and with the benefit of modern technology, GIA have determined that Lowers between 75% and 85% give the best light return.

It would appear Henry Morse, Marcel Tolkowsky, and GIA all came to the conclusion longer Lower Halves improve diamond light performance. From this it’s not difficult to conclude that in any OEC recut, for best light return, it would be smart to choose the longest possible Lowers consistent with your preferred facet pattern. If you like the pinwheel pattern my advice would be to make sure the Lowers are cut so they extend to the edge of the table and no shorter.

Here’s a LINK to a fabulous, mind blowing, and very informative video on this very subject from Jonathan @Rhino Weingarten when he was still with Good Old Gold. Jon went on to create the August Vintage brand of modern OECs.

 

[Lykame]

I remember watching that video a number of years ago when I was trying to understand these things for my own diamond hunt. It's absolutely a great video, but I additionally love your explanations because you take into account the fact that diamonds are 3D in your explanations - it's like you managed to explain the next step in the journey to that video. Kudos to you.

Now we just need to see some videos of your DW's amazing diamond in various different lightings!

 

[prs]

I remember watching that video a number of years ago when I was trying to understand these things for my own diamond hunt. It's absolutely a great video, but I additionally love your explanations because you take into account the fact that diamonds are 3D in your explanations - it's like you managed to explain the next step in the journey to that video. Kudos to you.

Now we just need to see some videos of your DW's amazing diamond in various different lightings!

Thank you! I agree it's time for some more photos, and maybe even a video if I can manage to take a good one. DW has to be in the right mood before she agrees to be my model. I'll see what I can do this weekend.

I can't explain why I'm still so interested in figuring out the science of OEC cuts. I've moved on to to calculating the angles of the Lower halves and how they determine LH length. I'm coming to the conclusion that back then they didn't have anywhere near the precision necessary to create a flower petal pattern. That's why they are so rare. If you find one, you will know for sure it was created by an absolute master craftsman with years of experience, and at the very top of his profession.