Searching for 2.5-3 ct cushion

[Acrata]

A very good comparison of the two types of cushions, one optimized for brightness and fire (SCHA) versus an 8 main with the same pavilion design structure but where more weight was preserved and symmetry and light performance wasn't as as perfect can be found below:

http://www.youtube.com/watch?v=vh0ad6dsDRk&fmt=22 (SCHA Bottom Left, 8 Main Thin Bottom Right).
http://www.vimeo.com/9188543 (1st diamond on left 8 main thin, 2nd diamond on left SCHA)

In the first video, the 8 Main Thin seems to be chosen for poor performance to make a point. Is there a video (non-simulated) that shows a SCHA against an 8 Main Thin with good LP? The second video appeared to show this but I had difficulty making a judgment because it was a simulation. That said, the 8 Main Thin in the second video looked decent to me.

When I mention LP, I consider it separate from apparent spread or surface area. Clearly both are important, I just personally think about them separately.

 

[ChunkyCushionLover]

A very good comparison of the two types of cushions, one optimized for brightness and fire (SCHA) versus an 8 main with the same pavilion design structure but where more weight was preserved and symmetry and light performance wasn't as as perfect can be found below:

http://www.youtube.com/watch?v=vh0ad6dsDRk&fmt=22 (SCHA Bottom Left, 8 Main Thin Bottom Right).
http://www.vimeo.com/9188543 (1st diamond on left 8 main thin, 2nd diamond on left SCHA)

In the first video, the 8 Main Thin seems to be chosen for poor performance to make a point. Is there a video (non-simulated) that shows a SCHA against an 8 Main Thin with good LP? The second video appeared to show this but I had difficulty making a judgment because it was a simulation. That said, the 8 Main Thin in the second video looked decent to me.

When I mention LP, I consider it separate from apparent spread or surface area. Clearly both are important, I just personally think about them separately.

The first video(youtube) is a simulation based on sarin scans of both.
The second video (vimeo) is a video shot by Rhino in the GIA diamond dock of several actual cut diamonds he once had in his inventory including 8 main thin, SCHA, 4 main CB and AVC.

In terms of performance and sizes of flash I prefer using an ASET image or video in various lighting (like the vimeo video) to measure performance and flash size. These are objective measures of LP unlike subjective salemanship comments by dealers. It is dangerous to judge LP from numbers on a grading report but there are certain rejection criteria that I have learned based on my own research in diamond design to be accurate in seperating potential top performers from the rest.

 

[ChunkyCushionLover]

CCL, thanks for the detailed commentary on the certificate. Do other people agree with the assessment that it is unlikely to have good (or even decent) LP?

When you start accepting less than top LP its becomes a tradeoff with many beauty factors(faceup spread, LW ratio, size of flash, profile, outline shape, etc etc etc). It isn't black and white and becomes very subjective.

I don't mind the discussion about H&A rounds, since I asked if there was a consensus about them. How about SCHA? Is there any consensus about whether they consistently outperform other cushions? SCHA "fakers" were mentioned. Are they labeled as SCHA or not?

Some vendors call many things HA when they are not. Some suppliers inscribe HA on a girdle when by their usage HA could mean anything. In the case of SCHA there is only one main supplier and a limited number of retailors who carry this brand, each one of them should be able to supply you with images to prove the stone meets the strict criteria of the brand and HA patterning.

Do I need to be concerned that some SCHAs are poorly cut?

You should be concerned about any vendor who tells you something is HA without showing you an ASET image and a Hearts and Arrows image.

I don't demand a patterned look, but I don't dislike it. I don't like crushed ice because it looks chaotic to me and the flashes are too small. The diamond we've discussed did not look like crushed ice to me.

If you have educated your eyes(by viewing other cushions the SCHA, 4 main CB etc.) and you still think this is the best choice for your budget than I see no reason to look further.

I believe there are stones that are neither obviously patterned nor crushed ice, and these would be fine for my needs. Do these diamonds exist, or am I confused?

Yes virtual facet size are a continuum and range from larger in the vintage styles to very small in the crushed ice type. Also many stones exhibit a range of size and distribution patterns. However a stone with the grading report you are considering will have LP flaws based on proportions these may include at least one of the following or all of them to some degree (excessive leakage, excessive obstruction, small average VF size, poor contrast, poor brightness, limited fire, a watery appearance).

You may be okay with these flaws and LP may not rank high in your selection criteria but I beleive in pointing these things out because your vendor who is trying to sell the stone most likely won't.

Performance does not equal patterning, performance doesn't relate correlate directly to brand versus non brand either. I have seen many cushions sourced by GOG that neither show HA patterning nor are they a brand, but they exhibit a superior level of optical performance and LP, a proverbial "needle in a haystack" if you will.

 

[Acrata]

The first video(youtube) is a simulation based on sarin scans of both.
The second video (vimeo) is a video shot by Rhino in the GIA diamond dock of several actual cut diamonds he once had in his inventory including 8 main thin, SCHA, 4 main CB and AVC.

Sorry, I mixed up the videos because I watched the vimeo one first. I meant to say:

In the second video, the 8 Main Thin seems to be chosen for poor performance to make a point. Is there a video (non-simulated) that shows a SCHA against an 8 Main Thin with good LP? The first video appeared to show this but I had difficulty making a judgment because it was a simulation. That said, the 8 Main Thin in the first video looked decent to me.

If you have educated your eyes(by viewing other cushions the SCHA, 4 main CB etc.) and you still think this is the best choice for your budget than I see no reason to look further.

My eyes are not educated, so I appreciate your opinion on this stone. I'm not in love with the diamond, but 3 ct with decent LP for $25k seemed attractive. 3 ct with mediocre or poor LP does not sound so good. I'm still looking for additional opinions about this diamond, so I can be confident if I tell the vendor I'm passing on it. Or if anybody thinks it is decent, I would like to hear that also.

Thanks again!