CBI vs ACA - Another pic and vid comparison

[erislynn]

Hi everyone! I always wanted to know if there was a marked difference between two very popular superideal brands here, ACA and CBI. And after @Drizzle posted some extremely helpful videos comparing them in these threads:

2.3 ct RBC diamond comparison: Crafted by Infinity, WF ACA, and James Allen (GIA 3X)

2.3 carat RBC dilemma - WF ACA with lower color/clarity OR "compromise" cut with JA?

I just had to see the difference with my own eyes. So I did, and I was dumbfounded! For a long time, ACA's were the gold standard of what I thought a superideal should look like. They are such reliably gorgeous diamonds that would never disappoint anyone, but when I saw a CBI for the first time, I was both puzzled and blown away. So recently, I was searching high and low for VERY specific proportions that I knew I preferred. We're talking CA/PA, table, LGF, depth to three significant figures. Turns out there was one CBI that was a match, so I figured why not?

When I opened my order from Wink, I was really worried that like in Drizzle's videos, the CBI would appear dark. But my first impression was that in a word, the sparkle was intense. I knew my set of proportions from an ACA before, and it did not have this bonus fire that the CBI was giving off. I also didn't remember this hyper-reflectivity of each facet that the CBI had. It was like if you imagine each facet is a mirror, the CBI had classic mirrors that reflect almost 100% of the light shining on them but the mirrors that don't catch any light are also completely dark. Hence, the high contrast look of CBI. Whereas ACA's (and "traditional" ideal RB's) have slightly frosted mirrors that soften the reflection of light but the mirrors that don't catch any light also don't appear as dark because of the frosted effect.









Unmounted ACA and Mounted CBI. Both G VS, no grade-making clouds. The third photo is the best I could do to show the difference in contrast. In person, it is more apparent. Sorry for the ugly hands.

Next here's a video showing the two under bathroom lighting. Based on this, can you guess which one has the higher crown angle?

It has been incredibly hard to capture this difference on camera. In person, what this boils down to is a softer, even-toned light pattern for an ACA and a more dramatic, contrast-y one for a CBI. There is definitely more fire on the CBI, if we're comparing matched proportions. And I can say this in an unbiased way because I actually don't prefer fire. So why did I keep the CBI? I was dazzled by the hyper-reflective facets. The white light return was so clear with a depth from the contrasting facets that I had never seen before. It's kind of like the first time you try dark chocolate. At first, the bitterness is a surprise but then you find it adds depth to the overall flavor.

Having said all that, they're both superideals and we're splitting hairs, but there is a difference. Now I'm wondering if anyone has a BGD Black for comparison?

 

[whitewave]

Interesting comparison.

All I know is when I wear my CBI I get not much done because my hand is in front of my face all the time lol.

But I have also seen ACA's on another person and they were super sparkly and distracting. Gorgeous.

 

[valeria101]

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May I ask if the HCA score of the CBI catches the extra contrast ? (BIC)

 

[diamondseeker2006]

Both stones look beautiful to me in the pictures! I honestly can't see any real difference in the photos. I originally thought you meant both had the same measurements and angles, but then when you asked which had the higher crown angle, I was confused. Because when the angles are different, people will have different preferences. Some like larger tables and more white light return, and some like high crowns and smaller tables and more fire. From the AGS reports I have seen in the past, I think CBI more often has crown angles under 34.5 and WF has more that are 34.5+ than under.

A BG black wouldn't be a good comparison because I think those are only D-F color.

 

[diamondseeker2006]

One more thought as I reread something you said: "Whereas ACA's (and "traditional" ideal RB's) have slightly frosted mirrors that soften the reflection of light but the mirrors that don't catch any light also don't appear as dark because of the frosted effect."

I am not sure what you mean about "slightly frosted mirrors". To me, that is an indicator that the diamond is not perfectly clean. Because I currently have 8 graded ACAs in my house (and have had about 6 others that I traded in), and I have never seen anything like frosted facets unless a diamond is dirty. In fact, my AVR gets frosted facets if I don't clean it regularly, as larger facets definitely show dirt more than small ones!

 

[Drizzle]

@erislynn

First of all, you so DO NOT have ugly hands! I just saw your other thread showing off your CBI solitaire (including hand shots) and I must say, the ring looks very pretty on your hands - classy, elegant, and timeless

and YES, finally someone that gets *me*!! I totally feel everything you're saying - the crispness, mirror like facet, and a very contrast-y look, subtle but noticeable difference, etc etc. and indeed it is extremely difficult to capture in photos/videos but I think you did a great job! Especially I think 1st & 3rd photo both showcases the subtle difference I saw IRL.

 

[ratatat]

Tbh in the photos and videos I can’t see a huge difference, but as you said this sort of thing so often doesn’t translate well in photos and videos, but has to be seen by the eyes. Interesting insights

 

[jadesilver]

Very interesting! Some of us will never get to compare ACAs and CBIs in person, so it’s very helpful and interesting to read your description of the differences. I think I can imagine it from your detailed description. Thanks for sharing this! They do look quite similar but i see that the CBI has more contrast.

 

[SimoneDi]

I am sorry but I also cannot really see a significant difference between the two stones. I am not sure what the exact sizes are, but I would almost match them for earrings because they look pretty identical to me. Nonetheless, I am glad that you see a difference and that you are happy with your new CBI diamond. Both stones are gorgeous!

 

[LLJsmom]

I am sure you see it IRL. The video is just fuzzy to me. Maybe my eyes are that bad. I will try again if you want to post another video.

 

[yssie]

Comparing scan output to three significant digits is not meaningful. Eliminating rounding and averaging from the discussion, the scanners used to acquire that data have larger error margins (to the tune of 1-2 orders of magnitude) - it is a case of precision without accuracy.

Ditto @diamondseeker2006 - I’m not sure exactly what you mean by “frosty” but usually that would suggest either more included material (not the case here) or that the stone isn’t perfectly clean... I would believe that one stone perhaps has more crispness of faceting than the other, but I personally do not see differences in those photos that I could not attribute to stone angle, depth of field, and focus region - as @ratatat said these are the sorts of observations that are difficult to convey through digital media!

 

[whitewave]

Speaking of clean, I ultrasonic cleansed my jewelry last night and this morning and I am currently at a jewelry appraiser and he has his assistant clean them all because they were too dirty.

They use Mr. Clean and water in his ultrasonic cleaner with 120degree water and let it soak
And clean and THEN he steam cleans it.

They had to do two pieces twice

So IMO it is very possible the ACA was dirty. I would have said my jewelry was clean this morning.

 

[erislynn]

@valeria101 The HCA for the CBI is a TIC.

@Drizzle Thank you for the kind words! I'm so glad we understand each other on this. Can't wait to see your finished ring!

@LLJsmom The video can appear fuzzy at standard res but is also available at 1080p which is much clearer.

I want to clarify that my observation on ACA's isn't based on just comparing these two stones for a few days. I have lived with an ACA and admired it over several hundred days. I know the look well and the difference I'm talking about is not chalked up to this particular ACA being dirty.

When I say "frosted" I merely mean to help people vizualize the intensity of light being reflected. I am not trying to say the ACA looks filmy as a whole.

There isn't meant to be a stark difference in the photos. It's a subtle one that is somewhat noticeable in the third pic if you look closely at the tables. When we photograph well cut GIA3x next to superideals in good light, it's also likely hard to see a difference. But many of us know there is a difference IRL. That's the type of subtle distinction I'm trying to describe here.

For those answering the poll question, take it as "all else being equal" how do you think the crown angles compare? Just wanted to know this for fun.

 

[egemnoel]

It will be very difficult to capture the difference in a video. Cameras make videos auto-darken around bright events. The CBI diamond needs to be really seen in the flesh it has that crisp reflection and a real fireball, explosive sparkles. For me personally it wins every time.

@erislynn you did the best thing and brought them home for comparison and let your eyes do the talking.

 

[cflutist]

WF ACAs and HPD CBIs are both superideal cut diamonds. I cannot speak to ACA but my 2.79 F-VS1 CBI has the crisp flashes that the OP talks about.
This video taken with Samsung S7 phone in our bathroom.
Zoom in to see the diamond more clearly.

 

[cherij0411]

WF ACAs and HPD CBIs are both superideal cut diamonds. I cannot speak to ACA but my 2.79 F-VS1 CBI has the crisp flashes that the OP talks about.
This video taken with Samsung S7 phone in our bathroom.
Zoom in to see the diamond more clearly.

What does CBI stand for? Thanks

 

[AprilBaby]

I didn’t read the post yet but the one in the ring is prettier to me. Now I’m going to see which it is.

 

[marcy]

I honestly don't see a difference in the photos or video. I think both ACA and CBI are gorgeous diamonds. I also imagine if any of us were comparing 3 CBI or 3 ACA in person we'd find one we prefer over the other 2.

 

[cflutist]

What does CBI stand for? Thanks

@cherij0411
Crafted by Infinity from High Performance Diamonds
A Cut Above from Whiteflash
Both are superideal diamonds

 

[gm89uk]

So what are the angles and tables for both stones? Thanks for posting

 

[gm89uk]

The ACA appears to possibly have the higher crown angle

 

[tanalasta]

My question is ... not all ACA's have identical proportions. We're comparing two diamonds. But not necessarily two brands. You'd have to select an adequate sample of both stones and perform a blinded assessment.

I think the ACA stone also appears to be a higher colour grade.

In real life, we only stair at the diamond in different lighting close-up when we first buy it (or admire it). Thereafter, it's very much from real life distances where all you're going to see is a bright, white stone and sparkle.

 

[erislynn]

My question is ... not all ACA's have identical proportions. We're comparing two diamonds. But not necessarily two brands. You'd have to select an adequate sample of both stones and perform a blinded assessment.

This is a testimonial, not an organizational study, so don't know how I would get multiple stones from each brand to compare.

I think the ACA stone also appears to be a higher colour grade.

Both are G.

In real life, we only stair at the diamond in different lighting close-up when we first buy it (or admire it). Thereafter, it's very much from real life distances where all you're going to see is a bright, white stone and sparkle.

Not if you're a PS'er. And not after all the work that goes into making a decision!

 

[tanalasta]

Thank you for the excellent comparison in any case. And as a PS’er I used to agonise over decisions. Now I let my rep at WF do it for me ...

Placing an order this weekend actually ...

 

[erislynn]

Thank you for the excellent comparison in any case. And as a PS’er I used to agonise over decisions. Now I let my rep at WF do it for me ...

Placing an order this weekend actually ...

WF reps are reliably honest with their evaluations. I can see why you trust your rep. Don't forget an SMTB!

 

[erislynn]

It looks like from the replies here, it's pretty evenly spread about how the crown angles compare. I thought that the CBI looked like it had a tad more fire (because IRL it did) and hence a higher crown angle, all else being equal. In actuality, the CBI was a 34.2, the ACA was a 34.6, same table size. I also had another ACA with 34.2, same table size, and the CBI still had the most fire out of the three. I did not expect this based on numbers, and as mentioned before was hoping for less fire. So when it was present, I really noticed it. The takeaway from this is that there is something special about the CBI cut beyond the usual specs and scope images we use to evaluate diamonds.

 

[cflutist]

I personally have not seen a WF diamond and cannot speak to them but this might explain why you are seeing more fire and dispersion in your CBI diamond. Way too technical for me to explain, in the realm of @John Pollard but I think that it boils down to this:
The Infinity team crafts diamonds with more fire by fine-tuning all of the internal mirrors in three-dimensions. This causes larger, unbroken internal reflections, boosting wider spectral fans of dispersion which are seen by your eyes as bigger, bolder bursts of fire. Infinity's fundamental better brightness benefit adds intensity, so you see more fire in more places, even in normal and low social lighting where other diamonds go dark.

https://www.hpdiamonds.com/en-us/education/education-crafting

Also when looking at the numbers remember that they are the averages of each crown or pavilion angle so the precision of each and all angles comes into play.

 

[HappyNewLife]

they both look great, I will take them

I don't know which is which, but the one in the actual ring setting looks better to me.

 

[Dancing Fire]

https://www.hpdiamonds.com/en-us/education/education-crafting

Also when looking at the numbers remember that they are the averages of each crown or pavilion angle so the precision of each and all angles comes into play.

I'd assume a precision cut like CBI will be very tightly cut. IOW, if you scan a CBI stone it should be very close from highest to lowest angles.

 

[Texas Leaguer]

I personally have not seen a WF diamond and cannot speak to them but this might explain why you are seeing more fire and dispersion in your CBI diamond. Way too technical for me to explain, in the realm of @John Pollard but I think that it boils down to this:
The Infinity team crafts diamonds with more fire by fine-tuning all of the internal mirrors in three-dimensions. This causes larger, unbroken internal reflections, boosting wider spectral fans of dispersion which are seen by your eyes as bigger, bolder bursts of fire. Infinity's fundamental better brightness benefit adds intensity, so you see more fire in more places, even in normal and low social lighting where other diamonds go dark.

https://www.hpdiamonds.com/en-us/education/education-crafting

Also when looking at the numbers remember that they are the averages of each crown or pavilion angle so the precision of each and all angles comes into play.

Yes, lab reports list the average of the various corresponding angles and percentages that make up a polished diamond. So basic numbers don't tell the full story of light performance, and certainly not of cut precision. This is especially true of GIA reports because numbers are rounded more than on AGS reports, nor is the GIA system capable of producing light maps.
This is why shoppers interested in the finest cutting need the additional information contained in light performance images, and other diagnostics such as computer ray tracing programs such DiamCalc and AGSL light performance analysis. VPA is an AGS tool that allows cutters, merchants, and consumers alike to easily understand where deviations in 3D precision exist and how far from target they are. It is also helpful in understanding whether the deviations are purposeful, such as indexing modifications designed to eliminate light leakage or to retain a point or two of critical weight, or whether it is random and a sign of less than superb craftsmanship.

Today, despite the romance vendors commonly seek to imbue their particular process with, there is really no mystery in the cutting of the modern round brilliant. The best parameters are known and it is just a matter of time, skill, advanced equipment, and a philosophy and commitment to precision execution that separates the super ideal strata from the ideal and excellent.