Ideal Cut Diamonds

22k yellow gold and boulder opal bead necklace

About a week ago one of the jewelers I know called me and asked if I could help her out with a customer she was working with.  She helps people trying to do a "do it yourself" project with jewelry sometimes (not something I recommend as inexperience in this field rarely leads to fine results but that's another story).  So she had a young gent who had managed to design a ring (nothing very original but that's also another story) on a computer using Cad-Cam and had a local casting company cast the piece up in platinum for him.  He had purchased three diamonds from an online company whose big thing is that they (supposedly---but that's yet another story) sell ethically sourced stones and jewelry.

The reason they came to me is because somewhere in the design to casting process some little beads had been added in on various parts of the ring that were not a design element and were not supposed to be there.  No one knew how they even got on there.  They weren't a mistake in the casting process as they were quite regularly placed.  Unfortunately they were regularly placed in areas where it was just about impossible to get them cleaned out of.  (Again, this is why I don't recommend do it yourself jewelry projects.)  He also needed to get the stones set into the four prong settings.  I don't believe in four prong settings because if you lose one prong you can lose the stone. If you have six prong settings you have to lose three prongs to lose a stone.  But when confronted with a design that only four prongs were going to work on (and this was one of them) I believe you need to make the prongs substantial enough that it is going to take quite a bit to knock one off or wear it down.  The prongs on this ring were nowhere near heavy enough, but again, this is why I don't recommend this kind of stuff (have I said that enough yet?).  So when no one else can do it, people like to bring it to me.  Sweet, huh?

But this isn't really about the ring itself. It's about ideal cut diamonds.  So what is an ideal cut diamond?

In 1919 a mathematician diamond cutter named Marcel Tolkowsky worked out a formula on what angles to cut a diamond to that would result in the maximum amount of brilliance, scintillation and fire in a diamond.  He figured out how the light would best travel through the stone and be reflected back out at the viewer by the facets below.  This involved a series of calculations, including the size of the table (the top flat area on a diamond) relative to the total size of the stone, the crown angle (the angle the top part of the diamond is cut to), the pavilion angle (the angle the bottom part of the diamond is cut to), and the crown and pavilion height percentage. An ideal cut diamond has to have the correct measurements in all of these categories in order to be considered ideal.

Tolkowsky had a cousin named Lazare Kaplan who was also in the diamond business and he went on to cut, promote and sell ideal cut diamonds and he was the first to do that.  The company he formed, originally Lazare Kaplan and now Lazare Diamond, has been in the forefront of many of the innovations in the diamond marketplace.  They developed the technology to laser inscribe the girdles of diamonds that is so prevalent today among other things.

Now when I started selling Lazare ideal cut diamonds about 25 years ago, hardly any diamonds (less than 1%) were actually being cut to ideal proportions. The primary reason for this was because when cutters cut a stone to ideal proportions they lose more weight from the rough than normal.  Most cutters, being paid by weight, just wanted to get the largest stone possible from the rough and since at certain sizes (.50 ct., .75 ct. 1 ct. etc.) there were significant price jumps just for hitting that weight, stones were often cut horribly just to hit the desired weight.

However about ten years ago, there was a subtle shift in the martketplace and the fourth "C"--cut--started to become more and more important as customers realized that the stone could be a "D" color, Flawless and still look bad if it was poorly cut.  However, as always seems to happen in business, as soon as people started to look for better cuts, the marketplace stepped in and began to "market" cut as well.  Unfortunately (and also as always seem to happen in business) this meant that once the term "ideal cut" was acknowledged as an important term, it began to be applied to any diamond that the companies thought they could get away with it.  They described stones as "near" ideal (a little like the idea of being a "little" pregnant) first.  Then as the Internet companies jumped into the fray they began to come up with more new terms like "super" ideal, "signature" ideal, or "insert company name here" ideal.

These are all completely bogus terms.  An ideal cut stone has to fall into the angles and sizes specified by Tolkowsky to be considered an ideal cut stone.  An excellent cut grade from the GIA or other gem labs is not necessarily an ideal cut stone.  It may be a well cut stone but it isn't an ideal cut. Actually some of the terms are slightly nuts.  One well known on line diamond site lists stones that are ideal cut and then others that are "signature" ideal cuts.  In looking over the angles on the stones it seems that what they sold as "ideal" cuts had no relation to a true ideal cut, but that the "signature" ideal cuts actually came in closer to what a true ideal cut should be. In other words the term "ideal cut" has been completely bastardized to fit whatever marketing gimmick the companies choose to use.

So back to my original story.  The young gent handed me the three stones he had purchased from the "ethically sourced" company and told me he had bought them as "super ideal" cuts.  The pricing on them seemed a little low for anything like that so I took a quick peek under the microscope at them.  It was immediately apparent that not one of them fit into the ideal category.  There is one thing you can look for on a diamond table that will almost instantly tell you if the stone is ideal.  A diamond's table that is in the 53%-57% range established by Tolkowsky as part of the ideal range will almost always have the lines that create the table bow inward surrounding it.  It took me less than 30 seconds to see this was not the case.  I confirmed it later using more advanced measuring devices but there was absolutely no way the stones would have been considered ideal cut by anyone who actually knew what an ideal cut is.

 So first of all how can the company call itself ethical if it's lying about what it's selling?  Secondly, while the stones seemed inexpensive for an ideal cut, they weren't actually ideal cut so there is no possible way the customer could have compared pricing to see if he was actually getting a good price.
The Internet is like the Wild West and there are very few controls on what is allowed.  I have personally seen more bogus information on metals, colored stones and diamonds then you could imagine.  My suggestion, as always, is to work with a local, well educated jeweler.  Work with someone you can talk to and who you trust.  It's always better to spend a little more but to know that you got what you paid for rather than just to look at a final price tag.

The ring, incidentally came out just fine when I was done with it.  You never would have known there had been some bizarre small bumps all over it.  I still wouldn't have made the prongs as thin as they were but there wasn't anything I could do about that.

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The picture above is of my wife's 25th anniversary present.  It's 22k gold with boulder opal beads.  But I can make one for you too if you'd like!