Well cut diamonds really do look bigger — even old cuts!

[Dreamer_D]

So recently I bought a couple of 4mm OECs on eBay. They had poor photos but GIA reports — diameters and table sizes matched, faceting was close enough for this size. I was hoping to use them as side stones for a coloured gemstone project. Unfortunately, the cut quality on one of them was simply too poor. I must be losing my touch because this is the first old cut I have bought that was not acceptable to me cut-wise!

The problem with the poorly cut stone is that its crown is too flat. It was kind of evident in the photos that the weight was all in the pavilion. I will pay more attention in future. I am returning it but keeping the other, which has absolutely perfect proportions

I might have lived with the poor cut because it’s an old stone and they are wonky, however, the old PS adage that poorly cut diamonds look smaller than well cut diamonds was so painfully obvious! I took a photo to illustrate.



Here are some more pictures of the pair because why not?? The well-cut stone has the smaller culet. It is a GIA H VS2! I love it.























I think the next photo also shows some of the problem as you can see the contrast patterning (lights and darks) does not extend to the periphery like it does on the better cut stone in the left.





Here you can see it’s flat crown on the right.


As you can see it looks pretty nice in the other photos! But I’ll post this one again just to close.

 

[Pomelo]

Oh wow, thank you for the detailed pictures! Your keeper is lovely and it’s always fun to compare stones side by side too hehe.

Out of interest, what were the GIA stats on the depth of the two stones, and could you have been able to identify the poor performer by depth percentage alone?

Also - your photos are fantastic! Just wondering what you’re using to capture these?

 

[0515vision]

Edge to edge brightness makes a huge impact! Thanks for the photos!

 

[Dreamer_D]

The diamond proportions checked out which is why I got it. Table 51% and depth 62%. What should have clued me in was this picture of the profile where you can see how shallow the crown is and how bottom heavy it is.




Compare to the keeper with very similar table and depth but this profile.



The angle of the two profile photos is a bit different which is why I discounted the potential red flags in the poorly cut stone. Ideally I would have been able to ask the vendor to take more photos, but the place I bought from sells for very very low prices and little customer service is the trade off. It cost very little so I rolled the dice.

 

[Pomelo]

The diamond proportions checked out which is why I got it. Table 51% and depth 62%. What should have clued me in was this picture of the profile where you can see how shallow the crown is and how bottom heavy it is.




Compare to the keeper with very similar table and depth but this profile.



The angle of the two profile photos is a bit different which is why I discounted the potential red flags in the poorly cut stone. Ideally I would have been able to ask the vendor to take more photos, but the place I bought from sells for very very low prices and little customer service is the trade off. It cost very little so I rolled the dice.

Wow, those macro profile shots really highlight the difference. Thank you for indulging me!

 

[Dreamer_D]

Here are some other interesting photos that may help others when trying to assess old cuts from static photos.

Please ignore the terrible picture of my engagement sapphire, she is not actually a lump of coal But you can see in the left diamond that the center went dark from the obstruction of my hand and head, but only the center. The better cut stone on the right is actually darker in this photo but that’s because its facets across the entire face are picking up and reflecting the black in front of it. The patterning of the black reflection in these pics is actually very similar to the pattern of light return in the original photo I posted.



Closer so you can better see the dark patterning.


You can see something similar in this hand shot too. The better cut stone on the left is showing dark reflection across its whole face whereas the other is only reflecting dark in the center but otherwise is just reflecting my skin from beside it.


And a reminder, in normal viewing where I’m not trying to take a photo holding my phone 4 inches from the diamonds, this difference in how the diamonds reflect light entering from straight-on looks like this:

 

[Pomelo]

You can see something similar in this hand shot too. The better cut stone on the left is showing dark reflection across its whole face whereas the other is only reflecting dark in the center but otherwise is just reflecting my skin from beside it.

Thank you, this is really helpful! Based on the photo alone, I would’ve picked the stone on the right but now I can see what you mean about the darker centre / lighter skin reflections.

Hmm now I wonder how many good OECs I’ve thought were actually duds, and vice versa…!

 

[Dreamer_D]

@Pomelo I’m glad it’s helpful! You kind of have to transpose the black for white light return when looking at this kind of picture. There is a flatness to the way the stone on the right handles light too that I hope you can see and for me that usually means not great contrast patterning. When buying from pawn shops and private sellers you have to learn to recognize the way a well cut stone looks in bad pictures and dirty too! Sometimes you can ask for a video or photos on the hand by a window or something. But then they may post the picture publically and you could lose out to another buyer. Always risks. But the price is so much lower from these types of sellers that maybe it’s worth it sometimes.

One way to train your eyes is take lots of macro photos and photos in poor lighting of old cuts you own. Look at how the light and dark is reflected and learn how the facet patterning appears in different lighting and with various degrees of obstruction. Every time you buy an old cut, even if you return it, take photos like I did so you can learn more.

 

[Dreamer_D]

This thread may be useful to people, as well as many of my old cut threads from 2013-2014.

This thread includes some of the terrible pictures of old cuts I bought along the way! One update: the thread includes some of my commentary about sellers color and clarity grading (and how it’s usually wrong). EBay’s new verification program may have changed that so take it with a grain of salt.

OK, some people have said they would like me to make a thread with my thoughts on buying old cuts.

I was hikacking someone else's thread in the interest of trying to explain something to TGal, and instead of doing that I thought I would start this thread.

I am by NO means trying to suggest I am any type of real expert on old cuts. I am not trying to suggest I know anything more than any of the other old cut lovers here on PS. I simply want to share some of my own observations and things I have learned buying old cut diamonds on ebay.

I will likely just copy some of my posts from other threads here, or update this from time to time. I am not really interested in approaching this systematically. That seems too much like work And frankly, I post on PS to avoid work.

So, in no particular order, here are some thoughts. Feel free to ask questions if you like, or add your own two cents, but perhaps if someone wants to open debate about a particular issue they can start another thread so that this one is easy to read for those people who specifically were interested in my ideas. However off base they may be

 

[bee24]

This is so helpful!