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WHAT’S A DIAMOND CULET?

LEARN WHAT A CULET IS AND WHAT IT DOES TO A DIAMOND

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What's a Diamond Culet?

If you look at a diamond report (aka certificate), you’ll see something interesting called a “culet“.

“A culet?”

It will be listed on a GIA diamond report under “proportions“, which is also listed under a category called “shape and cutting style“.

I refer to that whole section simply as “cut“, because it makes up the entire cut of the diamond.

The cut not only contains the culet, but it also contains fun things like the girdle, depth, table and finish. But for now, let’s just stick to the culet.

What is a culet?

Most people don’t know.

Most people just breeze by it on the report without giving it a second glance.

Is the diamond culet something to take notice of?

Yes, yes it is!

So let’s learn what a culet is…

The culet is a single facet on the bottom of the diamond.

One tiny facet that actually has a purpose and a very good purpose.

If you look at a diamond from the side view, you’ll see the diamond is divided into two sections by a line called the girdle. The top section is called the crown. The bottom section is called the pavilion.

The bottom part of the diamond looks like an upside-down triangle. This triangle is where all the lines and facets of the diamond meet and they come to a very sharp point.

Here’s a tip…

At the very tip of that point is where the culet is faceted. It’s at the very bottom of the pavilion and the cut is flat making the culet parallel to the table (which is the top flat window of the diamond) and girdle (see image).

What’s interesting about this is:

Not all diamonds have a culet.

It’s not a necessary cut.

It doesn’t affect the look of the diamond in the least (unless the culet is so large you can see it. But more about that later…)

The culet’s sole purpose:

The culet’s sole purpose to exist is to prevent the diamond’s vulnerable tip from chipping or breaking.

That’s it!

When any diamond comes to a sharp knife edge like the culet does, it can be chipped or broken easily. Usually this would happen during setting the diamond into a mounting (which is why you should always microscope or loupe your diamond once you get it back from the jeweler).

It’s a fact, chipping or breaking is what happens to sharp pointed diamonds (think marquise, think girdles). But, if that sharp point or tip is cut off (making a flat surface), then it will keep the end from shattering.

GIA diamond reports:

GIA will list whether or not the diamond has a culet. Trust me, you want a culet. Just knowing your diamond has one brings peace of mind.

GIA rates culets and size:

If the culet is None, Very Small, Small, Medium, Slightly Large or Large, you’ll be fine.

  • None = Excellent
  • Very Small = Excellent
  • Small = Excellent
  • Medium = Very Good
  • Slightly Large = Good
  • Large = Good

But if the culet is Very Large or Extremely Large then it’s a whole different story…

  • Very Large = Fair
  • Extremely Large = Poor

Bullet holes:

When a culet gets too large, you may be able to see that facet just by looking down into your diamond from the top view. And because the culet is the dead center of your diamond, it could get very noticeable. It may look like a little dot, pinpoint or even a hole. I refer to them as bullet holes because it looks like the diamond’s been shot.

Old mine cut diamonds and old european cut diamonds have Extremely Large visible culets on them to prevent chipping. But that’s because they were all cut by hand back then (before the 1900’s), before diamond saws were invented.

No culet:

If the diamond has no culet, it doesn’t affect the diamond report (or even price), it will just list it as “None“. No culet is fine as well, you just have to be more careful with them.

I would advise sticking with a small or medium culet if you can (just in case).

You don’t have to worry about chipping the diamond when you pick it up with a pair of tweezers. And after looking for months and months to find the perfect diamond, you get the perfect clarity and the perfect color (I prefer VS2 clarity, E color, with an excellent cut), do you know how bad it would suck to then have the jeweler accidentally chip the tip during setting?

Ouch!

That would smart.

(So don’t forget to always scope your diamond (or at the last use a 10x jeweler’s loupe) every single time you drop your diamond off for repair and every time you pick it up!!!)

So as far as the culet goes…

I’d say that’s the last cut.

Cheers! :)




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Ultrasonic Jewelry Cleaner Jewelry Steam Cleaner
Complete Jewelry Cleaner Kit Diamond Dazzle Stick
Gold Silver Jewelry Polishing Cloths Jewelry Making Supplies Kit
Gold Acid Test Kit Watch Tool Repair Kit
Ring Adjusters EMT Emergency Ring Cutter
10x Jewelers Loupe Jewelers Microscope

4 Comments on WHAT’S A DIAMOND CULET?

  1. Richard – Very concise, and informative, as always! But, I think one thing is missing. (This isn’t a criticism by any means – more of a request for information.)

    Suppose, after establishing with your jeweler that there is a small culet present, or even no culet facet at all, when you have had yourring in before for some kind of work. And then, after another visit, you retrieve your ring, all shiny and new looking again. But, by louping it, as directed, before leaving the counter, you find the culet is broken! Then what should you do? Refuse to pay for the work, because the damage has just downgraded the cut grade, or the clarity grade to an I-1?? Demand a replacement stone of identical pre-repair quality? Leap across the counter, and throttle the jeweler? (Only kidding – I certainly don’t condone violence under those circumstances!)

    But, seriously, what are your reasonable options in such an instance?

    • This is where things get tricky. This is also where preventive medicine will aid. First off, having a certificate is ultra-wise. That lists the condition of your center stone (and whether there is damage to the culet). If you don’t have an up-to-date certificate (aka diamond report), then an official gem appraisal on the stone is recommended (that would also list whether the stone was chipped). And then, after all your documents are in aline, then you’ll have to make sure you scope the stone when you drop it off to them, and have them document the condition on the repair slip. And then, once you retrieve it after the works been done, scope it again. If you notice it is chipped, you now have proof that the jeweler did it. And in that instance, their insurance would pay to have it replaced. In my opinion, this is the only way to really cover your butt. Having paperwork (and making sure to keep those reports current, not 20 years old…), and making sure the condition is noted before they touch it. Do realize one thing though, the only way they can really damage the culet is if the stone is removed, reset, or pushed down too far into the head. For a standard tightening, retipping, or straightening, the culet will never be touched or damaged. -Richard

  2. Richard- Thank you. I’m sure that your reply may encourage some folks to pay closer attention to the “paper trail” aspect of their diamond purchase. Even if it’s only one person, then that’s been very helpful.
    Fortunately for me, I only ever go to the same independant, family-owned local jeweler for any kind of work to be done on my rings and other pieces. The same one I have gone to for over 25 years! Their bench jeweler is in-house, and nothing ever leaves the store for work to be done.
    My rings have small stones – <.50ct – but they are good quality nonetheless, and I'd hate to have them damaged. But, the work I have had done on some of them – yes, more than one – has involved installing new heads, such as upgrading a small, low 4-prong setting to a somewhat taller, 6 prong illusion setting, just large enough to make the stone appear a good bit larger, but not large enough to be grotesquely obvious (I really hate those).
    Or, I had my mother's .75 ct YAG solitaire reset from a 4 prong to a 6 prong setting, because to my eye, the 6 prong solitaire setting makes the stone look much rounder than the 4 prong setting, which makes them look more square. It really improved the look of the stone a great deal. And it set it up just a bit higher than the older 1970's setting, which gives it more light!
    In any case, a good bit of the work I've had done, including things I haven't mentioned, did involve resetting the stones, and while I'm sure YAGs aren't of much financial value, there's certainly a personal, emotional value involved! I'd hate to have to try to replace it these days!

    (As a side note, on your post regarding "Girls Who Hate Diamonds," which just came out this morning, I noticed first, there isn't a "Leave A Comment" section, so I couldn't leave a comment regarding the fact that the line at the bottom of the text about linking to see more corundum stones isn't an active link, just plain text. If you want to take this part out of my reply, please do, as it has no relevance to the rest of the information.)

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