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Dead spot in ACA

blueMA

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If you place a white tissue in front of the diamond or wear a white shirt, the darker spot will probably disappear, which means it's simply reflecting what it sees directionally. It is not a "dead spot" so to speak and you're going from a >75 (GIA rounds up to near 5, so probably near 73 with the fat arrows and tight gap on hearts V's) to a more balanced 77 pavilion half lengths.

I'm sure the diamond is a lovely performer especially in brighter day to day light, so try not to obsess there's something wrong with it. Enjoy your ACA upgrade.
 

TreeScientist

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Just from the pictures alone, I prefer the performance of your original stone. I think a 34/40.8 combo is a great balance of brightness and fire. Your fiancé picked out one heck of a diamond. Any chance you could post a side-by-side comparison video? I would just like to see if there's any differences in scintillation or fire between the two.

I think @blueMA's description is the most likely explaination. Diamonds with clustering around the center of the arrow shafts (the blue circle in the center of the ASET) tend to exhibit a bit of a dark center at certain tilt angles. This is different from the entire diamond "going dark" in direct sunlight, which is something that pretty much all well-cut diamonds do.

Another (far out in left field) possibility is that the tiny amount of internal graining in your original stone is keeping the diamond well-lit at all times due to the light scattering caused by graining. Sort of like the silk in fine Kashmir rubies and sapphires gives them their "glowy" appearance. IMO a tiny amount of graining can be a positive for diamond appearance, as it makes them come to life in pretty much every lighting environment.

But determining whether the difference in appearance is due to the graining (unlikely) or due to the difference in cut (much more likely) is not something that can be done through the computer. :mrgreen:
 

Karl_K

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tiltynolighty.jpg
A diamond can only return light from a direction it is "looking" if there is little to no light from those angles you dont see it as bright.
 
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Gabbycat

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I bought and returned a couple of ACA's for this reason. I thought it was just an issue with the first stone until I got the second and had the same thing happen. They were without a doubt absolutely beautiful diamonds, but this effect with the tilt drove me absolutely nuts. Which is why I went for a transitional, chunkier cut instead. I did not seem to have the same problem with that stone. Not sure if that is the same experience of others here. I think the effect when the facets are "off" and the difference in contrast is not as severe and bothersome to me with the well cut older cuts. But each person is different, and when the modern brilliant stone is performing I can totally understand why people love them.
 

WillyDiamond

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Hold on.......OP you have to be happy with the stone. All the specs may look great. All the PSers may say the stone is a winner, but you are the one who has to look at it all the time. If you are going to look at the stone and be unhappy with what you are seeing, then I say return the stone to WF and start over.
Diamonds are expensive, you should be 100% happy. And WF wants you to be 100% happy so you will refer them and write wonderful stories about them on PS. Good luck.

Edit: There is an expression on this forum called "eye clean". It normally refers to inclusions. But I say if the stone is not "eye clean" to you, well then you know how I feel.
 

Gabbycat

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@flyingpig, maybe I'm misreading your intention in your post, but that seems pretty rude as it appears to be the equivalent of calling persons who see this in their diamonds and question why it happens as being stupid. One or two pics on the internet doesn't mean we see and opine what the OP does.

I have smaller ideals in a five stone band, and I LOVE them in that size. But the larger I went with the diamond the more pronounced what the OP is seeing became to me. Because of my PS education, I found the threads explaining exactly why this happened, and I understood and was fine with that explanation. I just didn't like how it looked. They were both around 1.2 carat ACAs, so I knew the choice and cut of stone wasn't the issue. Just my personal preference.

I love this site but really hate sometimes how some persons think it's funny to belittle others who simply have questions about what they see or maybe end up with a differing opinions about what everyone else feels is a "no brainer" stone. It's not a personal attack on the stones you have picked for yourselves. You all have beautiful diamonds. It just means that we have decided this type of cut/size/color/visual effect/fill in the blank isn't for us.

To the OP, as @WillyDiamond said, you have a beautiful stone, and now that you know why this happens and if you love it and want to keep it then keep it. But YOU have to be the one to love it. No one else gets to decide if it's the stone for you.
 

Caly27

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Hi everyone,

It’s been an interesting read (just reviewing now with all of the holiday rush), and I appreciate the time people have taken to respond. However, I think maybe it’s best that I just bow out of the thread. I’m sorry if this topic annoyed some people. I really was genuinely curious. And yes, the effect may be more pronounced with a darker color in front but I’ve also seen it in various other lighting. Otherwise, I generally love how the stone performs and plan on keeping it.
 

flyingpig

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@Caly27 @Gabbycat
Please accept my apology. My intention is not to offend anyone or be sarcastic. A diamond with known proportions behaves very predictably. And it is easier to understand if you view a diamond as a mirror. So, I posted a plain photo and asked a simple question that everyone can understand.

Regarding your (@Gabbycat ) experience, I fully respect that and believe what you saw. I think I have read it or even contributed to your thread (or maybe the other thread by other person). There were couple people who weren't satisfied with ACAs and one even compared ACA with CBI. In both cases, ACA's contrast was not as clear as CBI's.

Personally, I do not really care if someone likes and buys a shallow, super ideal, or deep stone. I have nothing against or for ACA. I am more interested in how diamonds behave, how diamond photography works and how ASET images translate to IRL viewing experience.
 
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Gabbycat

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@flyingpig, I appreciate and accept your explanation of your post. Intent is hard to get across on the internet. When I saw it I took it more as that everyone knows why the mirror is dark in that situation, so it should be obvious in a diamond. But I now understand your viewpoint, and I also apologise for assuming your intention first instead of asking what you meant before commenting. And to @Caly27 I am sorry if it was my reaction that made you leave your own thread.

I may need to go back and look to see if it is already pinned somewhere, but this may be one of those subjects that should be pinned for folks looking at buying super ideal diamonds. It seems to be a common question AFTER people receive their stones. I think people run into the same issue as I did in that, with the raves about the ideal cuts, I expected my stones to be "on" all the time in every lighting condition and at every angle. When you receive them and find that isn't the case, it is disappointing and somewhat confusing since it appears that everyone else's stones are always perfect. Does anyone else have thoughts about this?
 

Karl_K

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My wifey4vr went to bed so I grabbed her rings to play with... ssssssshhhhhhh don't tell her.
Her original pre pricescope diamond which I picked by eye and is a fic type stone, I had a very hard time getting it to do it but it did.
Her other is a super tight super-ideal and I got it to do it and could get it to do it every time.
My .15 melee in my ring it was super easy to get it to do it bur I tried it after the other 2.
 

Karl_K

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It seems to be a common question AFTER people receive their stones. I think people run into the same issue as I did in that, with the raves about the ideal cuts, I expected my stones to be "on" all the time in every lighting condition and at every angle. When you receive them and find that isn't the case, it is disappointing and somewhat confusing since it appears that everyone else's stones are always perfect. Does anyone else have thoughts about this?
I think that the push for super-ideals here does build unrealistic expectations in some cases.
Diamond performance is dependent on lighting, there is no getting around that.
My mantra for 15 years on here is that the top 5 things affecting diamond performance/looks are:
Lighting
Lighting
Lighting
Lighting
Cut.

You only see the best pictures on here not the culls.
 

gm89uk

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@Karl_K Would have thought a FIC type diamond would suffer more from obstruction having a shallower pavilion.
 

blueMA

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@Karl_K Would have thought a FIC type diamond would suffer more from obstruction having a shallower pavilion.

I believe smaller table, fatter arrows (as in the old cuts), and generally less clustering (the combo of pavillion angle, half length and crown half length) tend to exhibit less of the obstruction shadows under the table.

FICs, OECs and diamonds with fatter arrows optimized for fire tend to perform better in dimmer lights as well, but the cut difference also causes compromise in the brilliance/brightness as a trade off compared to TIC/BIC.
 
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Karl_K

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@Karl_K Would have thought a FIC type diamond would suffer more from obstruction having a shallower pavilion.
Not enough evidence to say one way or the other I do not know the angles of that diamond.
 

OoohShiny

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I think what this thread highlights is how it is difficult for inexperienced diamond buyers (which includes myself and probably the vast majority of PS members who are not in the trade!) to know how different cuts of diamonds behave and have their own 'flavour', especially away from the 'magic lights' of retail sales environments (which are often overtly 'high pressure' or at least feel that way to unconfident newbie buyers, such as myself, and therefore don't encourage one to dwell or look at lots of different cuts).

With experience (of a diamond in different lighting environments) comes understanding, of a stone's 'character' or the science or both, but gaining this experience requires time. As mentioned earlier, I don't feel there's anything wrong with changing one's mind based on time and experience, so it is good that the PS-recommended vendors have such good Returns policies :))

I do wish there was a way to get more 'hands-on' time with diamonds, but it seems impossible unless one undertakes the GIA training courses or has the time/ability/opportunity to work at a diamond vendor's shop! :(
 

Karl_K

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I do wish there was a way to get more 'hands-on' time with diamonds, but it seems impossible unless one undertakes the GIA training courses or has the time/ability/opportunity to work at a diamond vendor's shop! :(
It is tough, what I did was visit local stores during the slow periods and talked to them.
During those times it was mostly just the owners in the shop.
I told them I was fascinated by diamonds and wanted to learn more about them.
Some where more open than others.
A few we looked at and discussed every diamond in the place and when I got my IS scope we did it again.
Coin and gold shops were more open than many pure jewelry stores.
Sadly that generation is now retired and the younger ones do not seem as interested in visiting and sharing.
Part of it is with the near death of memo they have far fewer diamonds in shop.
 

blueMA

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I do wish there was a way to get more 'hands-on' time with diamonds, but it seems impossible unless one undertakes the GIA training courses or has the time/ability/opportunity to work at a diamond vendor's shop!

Just browse as many stones and jewelry shops whenever you can! ; )

It took me a long while before getting used to my H&A e-ring. I initially disliked how it looked so dark under certain lighting until I understood why it did that. However, its performance under most lighting (especially while grocery shopping) always made me fall back in love.

I also don't like diamonds with =< 40.6 pavilions because the shallow pavilion tend to accentuate the darkness under the table when viewed direct frontal (less on a tilt, obviously). This is the reason why I ended up seeking diamonds closer to 41 pavilion with less obstruction issues.

Just know that when you're buying a super tightly cut RB diamond, it's cut to maximize the performance uni-directionally, and I believe this is a bit of fault that may eventually change and evolve in the future.
 

LLJsmom

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I found a pic of the difference between a MRB and an OEC when tilted to exhibit obstruction.
This is an AGS H 000 and a GIA K OEC. Both are just at 3 carats.
B286FE3A-9732-4CC6-9405-A2FEA79BB119.jpeg

Tilted away
0983B21C-0729-40D9-BF5B-A346D631D1F0.jpeg

More head on
41D85D05-1803-43BC-975E-A2C85F4FB3FC.jpeg
 

Caly27

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Messages
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Just from the pictures alone, I prefer the performance of your original stone. I think a 34/40.8 combo is a great balance of brightness and fire. Your fiancé picked out one heck of a diamond. Any chance you could post a side-by-side comparison video? I would just like to see if there's any differences in scintillation or fire between the two.

I think @blueMA's description is the most likely explaination. Diamonds with clustering around the center of the arrow shafts (the blue circle in the center of the ASET) tend to exhibit a bit of a dark center at certain tilt angles. This is different from the entire diamond "going dark" in direct sunlight, which is something that pretty much all well-cut diamonds do.

Another (far out in left field) possibility is that the tiny amount of internal graining in your original stone is keeping the diamond well-lit at all times due to the light scattering caused by graining. Sort of like the silk in fine Kashmir rubies and sapphires gives them their "glowy" appearance. IMO a tiny amount of graining can be a positive for diamond appearance, as it makes them come to life in pretty much every lighting environment.

But determining whether the difference in appearance is due to the graining (unlikely) or due to the difference in cut (much more likely) is not something that can be done through the computer. :mrgreen:

Hi @TreeScientist ,

I wanted to respond—I tried to do a video. Not sure if it worked. Here's the link:https://imgur.com/a/gNHQRYz . My original ring needs a scrub--I've been slacking in the run up to the holidays on cleaning. But it really is a joy to see both though side-by-side. I wish I could afford to keep both of them. But I guess we all wish some version of that.
 

Caly27

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Messages
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@Caly27 @Gabbycat
Please accept my apology. My intention is not to offend anyone or be sarcastic. A diamond with known proportions behaves very predictably. And it is easier to understand if you view a diamond as a mirror. So, I posted a plain photo and asked a simple question that everyone can understand.

Regarding your (@Gabbycat ) experience, I fully respect that and believe what you saw. I think I have read it or even contributed to your thread (or maybe the other thread by other person). There were couple people who weren't satisfied with ACAs and one even compared ACA with CBI. In both cases, ACA's contrast was not as clear as CBI's.

Personally, I do not really care if someone likes and buys a shallow, super ideal, or deep stone. I have nothing against or for ACA. I am more interested in how diamonds behave, how diamond photography works and how ASET images translate to IRL viewing experience.

Hi @flyingpig ,

Thanks for your post, and my apologies for jumping to conclusions. It really is difficult to understand tone and intention sometimes through the internet. This is a great community, and I'm appreciative of the time people take to contribute and explain things to a newbie.
 

blueMA

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Checkout the video at 4:33 and 8:10 for side by side OEC and MRB cut comparison, albeit Moissanite.

upload_2018-12-27_13-18-8.png
upload_2018-12-27_13-19-38.png
 

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blueMA

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Hi @TreeScientist ,

I wanted to respond—I tried to do a video. Not sure if it worked. Here's the link:https://imgur.com/a/gNHQRYz . My original ring needs a scrub--I've been slacking in the run up to the holidays on cleaning. But it really is a joy to see both though side-by-side. I wish I could afford to keep both of them. But I guess we all wish some version of that.

Both your stones are knockouts. I do notice a bit more contrast patterns (including the clustering) in your bigger upgrade stone, but I don't think it's anything out of ordinary to be frowned upon.
 

blueMA

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More side by side comparison between diamond cuts.
upload_2018-12-27_14-6-46.png
 

TreeScientist

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Hi @TreeScientist ,

I wanted to respond—I tried to do a video. Not sure if it worked. Here's the link:https://imgur.com/a/gNHQRYz . My original ring needs a scrub--I've been slacking in the run up to the holidays on cleaning. But it really is a joy to see both though side-by-side. I wish I could afford to keep both of them. But I guess we all wish some version of that.

Both are beautiful stones, thanks for sharing! I really don't notice any difference at all in performance between the two in this video, except perhaps a little more fire coming off of your original stone. As you said, it's a shame you can't keep both, as both are knockouts. But such is life with non-infinite funds. :)
 
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