Cut and the 4Cs: answers from a diamond dealer (page 5 of 5)

Yes, it's true that gem labs don't give cut grades to any shape except round. But that doesn't mean they're all the same! You need to look for a stone that's correctly proportioned (in Marquise, you want a length/width ratio of 2:1, and a total depth between 60% an 68% or so), has minimal "bow-tie" effect (dark spots near the center of the stone), and returns a full spectrum of light.

If it helps, I have a 0.58ct DSI2 in stock. Nice stone.

Yes, shallow diamonds do look odd. In the industry, we call this "fish-eye." It happens when a diamond is cut too shallow, so the refractive angles are wrong, and not as much light is refracted out the top. You wind up with a dark spot in the middle of the stone, so the diamond looks like, you guessed it, a fish eye!

As for the Oscars, yes, those are real, and are typically on loan from a high-end jeweler looking for publicity.

That's a short question with a LONG answer. The shortest answer is... It depends. Some mom and pop jewelers are pretty aggressive, and will mark up diamonds as little as 20-25%. In a more normal scenario, 50-65% markups are pretty standard. If you go to a high-end name brand (Tiffany, Harry Winston, etc.), prepare to pay much higher markups than that!

I once had a client ask me to do a ring similar to what they saw at Harry Winston for $85k. I got a very similar diamond (same color, clarity, cut, GIA grading, everything, and slightly larger than what they had seen) and made the ring for $32k.

NO! With I2 clarity, there will be OBVIOUS inclusions to the naked eye. These inclusions will dominate the stone (at this low a clarity), and it will not sparkle or look like a diamond at all. You should avoid a stone like this, even if it's free! You're much better off getting a smaller stone than getting one this weak.

Bear in mind that 10 years from now, you won't necessarily care if you spent a few extra bucks on your wife's ring. But if it bothers you every time you look at it, you WILL care about that.

Yes, this diamond is eye-clean, but NO, you should not get it. Notice that it has Strong Blue Fluorescence. This means this diamond reacts very strongly to "black light" - which is a component of natural light, glowing blue. This blue glow will drown out all the other colors of the diamond's natural brilliance, and you will wind up with a flat-looking stone that doesn't sparkle. You might as well get a piece of plastic.

I recommend getting a lower clarity diamond (SI1 is clean enough that most people can't see anything with the naked eye, though YMMV), with high color (H+), a great cut, and no more than faint fluorescence.

Honestly, it depends on how strict a grading you're looking for, especially when it comes to cut. Personally, I think cut is very important - probably more important than the VS2 clarity, to be honest. I'd rather spend money on a cut that maximizes brilliance, and maybe find an SI1 stone that's still 100% clean to the naked eye.

The bottom line is that in a 1.5ct stone, you should be able to get closer to the $10k mark for something you can be really proud of. This assumes you are looking for a round stone. Other shapes are generally even cheaper.

If you want some more details and advice, feel free to PM me and I'll give you a call and talk you through it. Happy to help if I can.

Hi there! I'm a diamond dealer and jewelry manufacturer, and my family has been in the business for almost 100 years.

Honestly, there is a LOT to know about diamonds, and it's worth some time to get educated before spending $20k. This will take longer than a reddit post will allow, so feel free to PM me and we can talk off-line. For now, here are some quick answers:

1: No, there really isn't a "go-to" site. By definition, anyone selling online is a retailer, not a "wholesaler retailer."

2: As far as "value," there are two ways to look at this: resale value, and "bang for your buck." They are related, but not identical. For resale value, you will be primarily concerned with getting a "clean certificate." That is, something GIA certified, with no notes, comments, or issues what would complicate a sale. Something like a G color, VS2 clarity, with a really nice cut, will always be easy to sell. Then again, as far as "bang for your buck," I am usually an advocate of SI clarities (as long as they are clean to the naked eye) and high colors (ideally D-G). I tell people I work with "you need a loupe to see clarity, but you see color from across the room."

HOWEVER, in an oval cut, there is a more important consideration than either color or clarity, and that is CUT. Ovals are notoriously difficult to cut correctly, and most (90% or more) wind up with a significant "bow-tie" effect, producing dark spots in the middle of the stone. As an amateur, it will be very difficult for you to discern this until someone shows you, but you have to be really careful when you buy an oval. Putting a stone with a bad bow-tie next to one without this issue makes the difference really obvious.

3: That depends. Are we talking about a simple solitaire? That would be a few hundred bucks. Something with pave and some diamonds on the shank? Maybe $2k. Something with large side-stones, colored diamond accents, or more elaborate work? Sky's the limit. Once you know what design (roughly) you're going for, this will be easy to figure out.

4: No, I don't think that's too big. But that's largely a question of lifestyle. For reference, my wife is about the same size (5'4", 115 lbs - I hope she doesn't kill me for saying that!), and she wears a 2.75ct stone. It looks big, but not TOO big. Then again, we live in LA, and I do this for a living, so maybe my perspective is skewed.

Honestly, I think there's a lot more to know here. I'm happy to talk with you and educate you a bit, so you know what questions to ask moving forward, and how to evaluate the answers once you get them. Let me know if you're interested...