Diamond spread discussion

[strmrdr]

This is my personal opinion mixed in with some facts to open a discussion on this subject.

We often hear that a diamond don''t face up like it should or has bad spread.
How does one define bad spread?
You can compare it to another combination of proportions as is currently done.

My opinion is that is not the correct way to do it.
Trading spread for a different look or a different performance curve is a legitimate thing to do if it achives the effect you want and find beautiful.
The correct way of doing it in my opinion is looking at what the diamond is giving in performance and looks then balance that against the spread.
But putting this in a cut grading system is hard which is why the current system is in use.
I think that the current system is keeping a lot of beautiful combinations off the market along with yield from the rough.
Yield can be dealt with as it is today by picking the best shape for any given rough when cutting it and high yield cuts are possible in this category.
The in my opinion artificial spread criteria is much harder to deal with and move beyond.
I envision a future where diamonds may be as custom as settings are today and designer diamonds become a reality with diamond designers working with setting designers and cutters as a team.
Instead of heading in that direction roadblocks are being put in the way like spread specifications.
This is also the huge downside of cut grading which spread is a part of and it puts the brakes on innovation.
What about performance grading?
Performance grading is a great advance and I am all for improved cut quality but forcing all variations into one mold with proportion limits is not the way to do it in my opinion.

Discuss :}

 

[JulieN]

I think it's fine to trade spread for a different performance or look.

This is easy to explain in the case of rounds.

However, don't you think it can be very difficult to explain to a consumer exactly where and how the look/spread exchange is happening when you have different CAs and PAs in certain fancies?

 

[John P]

Good topic Strm.

First thought: For new consumers “spread vs carat weight” advice is a good thing because it prevents them from buying the X-carat diamond that faces up small and performs badly for a seemingly “bargain price.” An example of this is the HCA spread calculation. Garry has applied a spread template based on the assumption users want the largest face-up appearance combined with optimum performance. That’s probably a good assumption in most cases.

When it comes to proprietary cuts or acquiring a desired look to performance I think you're right on.

Please add Depth% to the spirit of this thread in shapes where pavilion faceting is variable. For some reason there are people who can’t absorb the fact that Depth% is NOT related to spread in a princess (example) like it is in a round. Two princess cuts can have the same weight and spread but quite different depths. I regularly come across pros to whom this is a new revelation. Just like the outdated fluorescence stereotype it's an infection bred into the trade that is slow to be cured.

For some time I have trained salespeople to talk in terms of spread. This makes more sense to me than weight, which is an approximation at best. Three 1ct G VS2 rounds can face up 6.2, 6.5 and 6.7 mm respectively but we call them all 1ct G VS2. It opens new shoppers’ eyes when an expert explains that the 1ct diamond they found the “best” price on is visibly smaller. If we all described avg spread rather than (or along with) carat weight all of these things would be much easier across the board, including cuts where weight is distributed differently. You wouldn’t have to get out an abacus or explain that “in such-and-such shape 1ct appears smaller...” after the fact: It would be self-evident.

 

[strmrdr]

Date: 6/13/2008 1:50:45 PM
Author: John Pollard
Good topic Strm.


First thought: For new consumers “spread vs carat weight” advice is a good thing because it prevents them from buying the X-carat diamond that faces up small and performs badly for a seemingly “bargain price

I feel we may be throwing the baby out with the bath water.
For example the 50% tabled high crowned round you were discussing in the thread that prompted this thread.
Cut right that would be an awesome diamond.
Lets say a cutter has a rough with a broken top so there was no way to cut a second diamond from it, shouldn''t a 50% tabled high crown round be an option for that cutter?
Under the current system it isn''t and both the cutter and consumers lose out in my opinion.

 

[strmrdr]

Date: 6/13/2008 1:44:43 PM
Author: JulieN
I think it''s fine to trade spread for a different performance or look.


This is easy to explain in the case of rounds.


However, don''t you think it can be very difficult to explain to a consumer exactly where and how the look/spread exchange is happening when you have different CAs and PAs in certain fancies?

Yes fancies are harder especially where depth is not an indication of spread.
But the same problem comes into play X cut is bad because it doesn''t have the spread of Z cut.

 

[John P]

Date: 6/13/2008 2:11:23 PM
Author: strmrdr

For example the 50% tabled high crowned round you were discussing in the thread that prompted this thread.
Cut right that would be an awesome diamond.
Lets say a cutter has a rough with a broken top so there was no way to cut a second diamond from it, shouldn't a 50% tabled high crown round be an option for that cutter?

Yes. There will be far, far fewer of them than 60-60 makes but yes.

Date: 6/13/2008 2:11:23 PM
Author: strmrdr

Under the current system it isn't and both the cutter and consumers lose out in my opinion.

? All three above can earn AGS 0 light performance.

GIA excludes anything with table
If you're talking HCA you're right: A small number of specialty cuts get penalized alongside a massive number of steep/deep bad performers in the name of consumer protection. It reminds me of GIA's brillianteering judgment.

 

[strmrdr]

Date: 6/13/2008 2:31:13 PM
Author: John Pollard

Date: 6/13/2008 2:11:23 PM

Author: strmrdr


Under the current system it isn''t and both the cutter and consumers lose out in my opinion.

? All three above can earn AGS 0 light performance.

Yes, but if the cutter wanted to cut a reasonable 2.1 girdle or a 35.5 crown angle it would get downgraded to 1 for proportions.
35.5 40.75 50 gets similar diamcalc performance ratings to the modern tolk with the same lgf% so it would likely hit 0 in performance.
While the AGS system is a little better that the cutter being extra careful could get the overall 0 grade it is still a problem.

 

[John P]

Date: 6/13/2008 3:18:48 PM
Author: strmrdr

Date: 6/13/2008 2:31:13 PM
Author: John Pollard

? All three above can earn AGS 0 light performance.

Yes, but if the cutter wanted to cut a reasonable 2.1 girdle or a 35.5 crown angle it would get downgraded to 1 for proportions. 35.5 40.75 50 gets similar diamcalc performance ratings to the modern tolk with the same lgf% so it would likely hit 0 in performance.

While the AGS system is a little better that the cutter being extra careful could get the overall 0 grade it is still a problem.

I think this is where the labs' job ends and an experienced hobbyist or seller comes into play.

Example: Many diamonds simply won't take an ideal level of polish due to graining. Completely invisible, it's an unavoidable physical property of some crystals. Such diamonds get a 1 in finish rather than 0. As experts we explain this, and often extend a slight discount with no visible trade-off whatsoever.

In your example the 1 in proportions is, in my opinion, a more appropriate flag since there is some trade off in apparent size. Negligible as that may be the lab is doing their job. It presents an opportunity for experts to explain the somewhat different proportions while underscoring the most important factor - performance - which has received the highest mark.

 

[strmrdr]

Date: 6/13/2008 3:35:39 PM
Author: John Pollard
I think this is where the labs'' job ends and an experienced hobbyist or seller comes into play.


Example: Many diamonds simply won''t take an ideal level of polish due to graining. Completely invisible, it''s an unavoidable physical property of some crystals. Such diamonds get a 1 in finish rather than 0. As experts we explain this, and often extend a slight discount with no visible trade-off whatsoever.


In your example the 1 in proportions is, in my opinion, a more appropriate flag since there is some trade off in apparent size. Negligible as that may be the lab is doing their job. It presents an opportunity for experts to explain the somewhat different proportions while underscoring the most important factor - performance - which has received the highest mark.

In your opinion are their enough experts that understand this well enough to sell them for the cutter to take the chance?

 

[John P]

Date: 6/13/2008 3:44:00 PM
Author: strmrdr

In your opinion are their enough experts that understand this well enough to sell them for the cutter to take the chance?

No. We're working on it, but this is a severe issue. And you're right, it limits the number of such chances taken in the mainstream.

You know, applying that globally, the decicion to cut a brand with more labor/weight loss is taking a chance as well. Take any one of the top H&A brands: Those diamonds could be more-easily moved in the mainstream finished in less time with less consistency/precision and a lower markup.

Your example is more to the point, since the H&A "niche" has more vocal popular advocacy than your high crowner. In both cases, though, specialty cutters must partner with select dealers who can explain the make's features and benefits.