Role of Leakage & Obstruction in Step-cut Facet Patterns?

[Lula]

Calling all step-cut experts!

I've looked at many, many step-cuts over the years -- both in person and on PS vendor websites. What I've found is that even though step-cuts have fewer facets than many other cuts, there seems to be more variance in the "personality" of each stone than in other shapes. I know that some of the variance in appearance is a result of cutting for weight (rather than beauty) which is the same for any other shape. But what I don't understand is if step-cut cutters use leakage and obstruction to purposely obtain the patterns that we see, especially in the case of step-cuts that have not-so-great depth and table percentages or angle combinations. Personally, I think it all comes down to facet patterning with step-cuts, because most people aren't choosing a step-cut for its "sparkle." As all step-cut lovers on PS know, the numbers and the ASET and IS images "don't tell the whole story" and each stone has to be assessed individually. With rounds, I know that given excellent symmetry, certain sets of angle combinations will produce RBs with strikingly similar "personalities." This doesn't seem to be the case with emerald-cuts or asschers. So, after all this blather, my question is, are cutters able to (and do they) use leakage and obstruction to their advantage to cut step-cuts that exhibit a specific pattern, or is the facet pattern simply a by-product of the percentages and angles? I realize I'm treading into "what is beautiful?" territory, but I'll take that chance...

Thanks for your input!

 

[diamondloveaffair]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

yes, cutters do so. That's how many branded step cuts come about. Each has its own distinct patterns to them. The main driving force for cutting a diamond still lies in weight retention. Diamonds are seldom cut for light performance. The only reason why you see so many with good light performance here is people know what to look out for and actively search for them.

 

[chrono]

Re: Role of Leakage & Obstruction in step-cut facet patterns

I highly doubt they are cutting for pattern; they are cutting to maximize the yield of the rough, hence we see many MANY wonky ugly patterns, off-symmetry and the like. Unlike RBs, there is very little push for high performing ECs and I see far more duds than well cut diamonds. Finding a top performing EC is like trying to search through hay to find a hen's teeth. It makes little sense to deliberately use leakage and obstruction as a factor in cut angles. It is a matter of trying to make the best with what nature has given the lapidary. Branded cuts are a different category and thus sell for a premium. They are cut to very specific angles consistently for that look.

I don't know about most people but I purchase ECs for their sparkle. Perhaps most people choose ECs for the pattern because they have not seen the amazing sparkle and flash that a well cut EC exhibits. A well cut EC can easily rival a well cut chunky cushion in terms of sparkle. Numbers definitely do not tell the whole story and the ASET helps piece it together better. If lab reports start listing crown and pavilion angles, I think it will go a long way in helping us categorize ECs into groups with similar personalities much the same way RBs are. As of now, there is insufficient information for fancy cut stones other than depth and height. I don't think we'll ever get a standarized EC cut due to the low demand (compared to other shapes).

 

[Lula]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

yes, cutters do so. That's how many branded step cuts come about. Each has its own distinct patterns to them. The main driving force for cutting a diamond still lies in weight retention. Diamonds are seldom cut for light performance. The only reason why you see so many with good light performance here is people know what to look out for and actively search for them.

Thanks for the reply, DLA. I completely forgot about branded ECs, like the Tycoon cut. Also, I do agree with you that PS is a biased sample in terms of stones cut for beauty rather than weight. That's why I am always a little shocked when I see the selection at local jewelry stores.

 

[Karl_K]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

I could write a book on this subject and did write a couple articles
The virtual facets and how they handle light defines the patterns in a step cut.
Start here:
https://www.pricescope.com/journal/virtual-facets-and-patterns-discussion-about-step-cuts
Then here:
https://www.pricescope.com/journal/performance-and-p3-facets-discussion-about-step-cut-diamonds
Those articles just barely scratch the surface.

 

[Lula]

Re: Role of Leakage & Obstruction in step-cut facet patterns

I highly doubt they are cutting for pattern; they are cutting to maximize the yield of the rough, hence we see many MANY wonky ugly patterns, off-symmetry and the like Agreed -- the lack of symmetry in most ECs really surprised me -- it seems sloppy, especially in a stone with so few facets. Unlike RBs, there is very little push for high performing ECs and I see far more duds than well cut diamonds. Finding a top performing EC is like trying to search through hay to find a hen's teeth Ditto this! . It makes little sense to deliberately use leakage and obstruction as a factor in cut angles. It is a matter of trying to make the best with what nature has given the lapidary. But could good cutters use obstruction and leakage to compensate for the crappy angles and poor symmetry, or to make up for what nature didn't give them? Not sure if that makes sense. Branded cuts are a different category and thus sell for a premium. They are cut to very specific angles consistently for that look. Yes, but although the branded EC cuts are pretty, they don't say "EC" to me.

I don't know about most people but I purchase ECs for their sparkle. Perhaps most people choose ECs for the pattern because they have not seen the amazing sparkle and flash that a well cut EC exhibits. A well cut EC can easily rival a well cut chunky cushion in terms of sparkle. Yes, I've seen an antique EC stone with a very high crown that had large, chunky flashes, but it was much more asscher-like in appearance. Re fire and patterning -- how much is personal preference versus cut quality, especially when there are no agreed-upon standards for what is ideal in fancies? . Numbers definitely do not tell the whole story and the ASET helps piece it together better The ASET definitely reveals duds, especially when buying online. But so much of an EC's performance relies on how the facets light up when the stone is in motion, and the ASET is a static view of the stone, correct? . If lab reports start listing crown and pavilion angles, I think it will go a long way in helping us categorize ECs into groups with similar personalities much the same way RBs are. Agreed!!!!!!! And this is no doubt true for all fancy-cuts. As of now, there is insufficient information for fancy cut stones other than depth and height. I don't think we'll ever get a standarized EC cut due to the low demand (compared to other shapes) Which is a shame.

Thanks, Chrono. I always appreciate your perspective. I believe I read an old thread where Karl K. described three basic types of step-cuts (from his experience) -- something like the antique style, the classic cut...I can't remember the third. If I find it, I'll share the link. Or Karl -- just save me from doing a PS search and chime in if you're reading this

 

[Lula]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

I could write a book on this subject and did write a couple articles
The virtual facets and how they handle light defines the patterns in a step cut.
Start here:
https://www.pricescope.com/journal/virtual-facets-and-patterns-discussion-about-step-cuts
Then here:
https://www.pricescope.com/journal/performance-and-p3-facets-discussion-about-step-cut-diamonds
Those articles just barely scratch the surface.

Hi, Karl! Thanks for the links. I've read the p3 facets article, but had not seen the virtual facets article. I'll take a look at it.

ETA: That virtual facet article describes what I'm trying to get it. My question is -- how much of patterning (virtual facets) is a lucky accident and how much is planned for in the execution of the cut, especially in cases where the size and shape of the rough and the nature of the inclusions present cutting "challenges"?

 

[Karl_K]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

Diamond cutters based on past history have many different sets of proportions saved that have made beautiful diamonds in the past. They are passed down for generations from master to apprentices often from father to son. However they are not suited to every kind of rough and ones persons opinion of a great cut may not match what someone else would consider a great cut.
Having talked to people who have sat down and sorted through a cutters entire production they said they could tell at a glance when the cutter was able to follow one of their plans and when they had to push it to make weight.
The difference in performance and looks was night and day.
Another factor comes into play here and that is something like this:
Dad comes up with a great plan that results in awesome cuts.
Son learns to cut them and thinks hmmm if we change this we can gain a couple tenths in weight and make more money.
Pretty soon the result do not match the original design/plan.
Someone comes along and says I will pay extra for better stones like your Dad used to cut but the plan for producing the originals was lost over time and the cutter decides it is too big a hassle to reinvent them.

On the other hand you have an adventurous master cutter who cuts a design a consumer posted on an internet forum and a new branded cut is born.

 

[Lula]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

Diamond cutters based on past history have many different sets of proportions saved that have made beautiful diamonds in the past. They are passed down for generations from master to apprentices often from father to son. However they are not suited to every kind of rough and ones persons opinion of a great cut may not match what someone else would consider a great cut. Yes, this is where personal preference and differences in the stones' "personalities" comes in.
Having talked to people who have sat down and sorted through a cutters entire production they said they could tell at a glance when the cutter was able to follow one of their plans and when they had to push it to make weight. This is fascinating. I'd like to see a sort like this in person someday -- seems like a good way to learn
The difference in performance and looks was night and day.
Another factor comes into play here and that is something like this:
Dad comes up with a great plan that results in awesome cuts.
Son learns to cut them and thinks hmmm if we change this we can gain a couple tenths in weight and make more money.
Pretty soon the result do not match the original design/plan.
Someone comes along and says I will pay extra for better stones like your Dad used to cut but the plan for producing the originals was lost over time and the cutter decides it is too big a hassle to reinvent them. But tastes change, so as long as the plans aren't lost or destroyed, some forward-thinkng cutter could revive them

On the other hand you have an adventurous master cutter who cuts a design a consumer posted on an internet forum and a new branded cut is born. Indeed! And how cool was that?

 

[chrono]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

I don't know if diamond cutters do that deliberately or it is a lucky coincidence. Perhaps just having good symmetry is all one needs to get a nice pattern, not necessary a good cut. Yes, I think branded ECs are done in such a way to make them apart from regular ECs and make them flashier. Something akin to asscher versus Octavia. As pretty as those are (no offense to Karl and those who adore this cut ), they don't strike me as an asscher anymore.

I wonder if what you are seeing with antique ECs have anything to do with the size as well. All those I've seen are honkers! Hard to say about personal preference versus cut quality. For example, there is a strong preference for a certain type of RB here on PS (H&A or close to H&A) with many pooh-pooing the older 60/60 cut. Nothing wrong with that at all as I know there are excellent 60/60 performers out there. However, the difference is that the ASET or IS says it all. There is enough information to prove that the other style has good performers, not just liking one pattern or style more than another. Education is key and more people know about well cut rounds than well cut ECs. Am I making sense? Few even know that well cut ECs exist!

ASET might be a static snapshot but it takes light coming in from all angles into consideration, hence direct light and angled light.
https://www.pricescope.com/journal/aset-%E2%80%93-diamond-evaluation-tool

I think Karl has discussed several types of square asscher cuts in the past. Drop style comes to mind as one of them.

 

[Lula]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

I don't know if diamond cutters do that deliberately or it is a lucky coincidence. Perhaps just having good symmetry is all one needs to get a nice pattern, not necessary a good cut. I wonder about this, too. As someone who appreciates precision cutting, the mismatched an uneven facets I see in most ECs is really bothersome. I can't help but think it affects the virtual facets and the amount of colored flash and sparkle in the stone. Yes, I think branded ECs are done in such a way to make them apart from regular ECs and make them flashier. Something akin to asscher versus Octavia. As pretty as those are (no offense to Karl and those who adore this cut ), they don't strike me as an asscher anymore.

I wonder if what you are seeing with antique ECs have anything to do with the size as well. All those I've seen are honkers! Yes, same here. Huge stones. Which is why I'm not sporting one on my finger! One was a long, narrow EC that had the most beautiful undulating -- that's the only word for it -- scintillation. Large, even bars of color, and big, slow flashes of color. It was...sexy. That stone had a larger table, and probably an average crown height. I saw it in a high-end jewelry store. The other stone was more square, with a very high crown that looked "stacked" -- like a cushion with fewer facets. That diamond belonged to a friend's grandmother. Hard to say about personal preference versus cut quality. For example, there is a strong preference for a certain type of RB here on PS (H&A or close to H&A) with many pooh-pooing the older 60/60 cut. True! Nothing wrong with that at all as I know there are excellent 60/60 performers out there. Yes, I've seen them, and they are really very pretty -- and as I get older, I find I like the brightness of 60/60 stones more than the small-tabled Tolk stones beloved by most PS'ers However, the difference is that the ASET or IS says it all. There is enough information to prove that the other style has good performers, not just liking one pattern or style more than another. True, and what's interesting is, many people don't believe that a 60/60 or a 35 crown 41 pavilion stone can have good ASET or IS images --but those stones do exist. Education is key and more people know about well cut rounds than well cut ECs. Am I making sense? Yes, you are. Few even know that well cut ECs exist! For better or worse, I believe that The Great Gatsby and all-things-Deco craze may change that, i.e., there may be more ECs (and asschers) cut, but will they be better in terms of cut quality (and, of course, the price may go up!)

ASET might be a static snapshot but it takes light coming in from all angles into consideration, hence direct light and angled light.
https://www.pricescope.com/journal/aset-%E2%80%93-diamond-evaluation-tool

I think Karl has discussed several types of square asscher cuts in the past. Drop style comes to mind as one of them. Yes, that's the type of thing I was referring to -- only he was speaking of ECs. It may be helpful to figure out some way to categorize the "types" of ECs, similar to the way we talk about 60/60 versus Tolkowsky cut round brilliants

 

[Karl_K]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

I do have a classification for EC, classic and modern however I'm working today so it will have to be this evening or maybe tomorrow unless someone can find the last time I posted it.

 

[Rockdiamond]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

Great topic Lula!!
I think that there's so much misunderstanding of how and why a diamond looks as it does.
There's a common thread here at PS- some diamonds are cut for weight, others for light performance.
In fact, financial performance has to be paramount.
EVERY diamond is cut considering weight retention. If a cutter ignores this aspect, they won't be a cutter long.
The process might be: Well, we can cut a round which sells for this amount, or a radiant that sells for this amount.
Even specialized cutters need to pay attention to whats left after they've polished- even if they're cutting for excellence in cut.
They can sell a "super ideal" 1.00 for more than a "regular" GIA triple EX weighing 1.10cts- bottom line is the bottom line.
There's a balance between weight retention, beauty and saleability.
To say that diamonds are seldom cut for light performance is too broad a statement IMO. It really depends where one is looking, what shapes, so many factors.
If we use the pool of diamonds that are actually listed with pics online, as many people reading this will do, I don't feel it's accurate to say that cutters are not concerned with how the stone looks.
"Light performance"= personal preference.

I've had the experience of looking through thousands of stones of a cutters stock- and it's easy to see stones where the balance was tipped to far in the direction of weight retention. I find a similar experience when I see a really badly cut stone photographed and shown online,
I agree that more emerald cuts will fall into this category compared to other shapes. Having said that- it's pretty tough to sell a 1ct stone that looks like .75cts......I'm sure someone buys them....but IME the best cutters need to avoid such stones, and do.


People are talking about "branded emerald Cuts"- I am not familiar with any branded EC's - which does not mean they don't exist, but I've not seen them advertised. Once additional facets are added on- such a Tycoon, I don't believe GIA will classify the stone as an Emerald cut- but I'm not positive about that particular cut.

One of the things I love the most about emerald cuts is the fact that there's so much variation. Moving- or adding- facet breaks on the pavilion can give the stone a super "steppy" look even though "the numbers" may not be there.
For example, crown height- sometimes creative use of facet breaks makes a shallower stone look like a deeper one- and shallow is sometimes good at preserving more spread.
This is one of the main reasons that even if one knows CH/PA, it won't allow classifications as we do with rounds ( HCA ie)
In other words, higher crown small table will NOT always equal better cut than large table lower crown.

Makes life more interesting yes?

 

[chrono]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

Having said that- it's pretty tough to sell a 1ct stone that looks like .75cts......I'm sure someone buys them....but IME the best cutters need to avoid such stones, and do.

Plenty of people purchase 1 ct ECs that face up as large as a 0.75 ct EC. It took me forever to find an EC that isn't only a good performer but faces up correctly for its carat weight. A 1 ct EC (supposing a generic ratio) should measure 7 x 5 mm but almost all the 1 ct ECs I looked at both online (in stock and dropshippers) and at B&M stores are closer to 6 x 4 mm which is a 0.75 ct EC measures. When I was shopping for a potential upgrade to a 1.5 ct EC, almost all of them measure at 7 x 5 mm which is the same size as my 1 ct EC. Therefore, there was absolutely no incentive for me to pay more for a stone that is the same size as my current stone.

 

[Rockdiamond]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

Having said that- it's pretty tough to sell a 1ct stone that looks like .75cts......I'm sure someone buys them....but IME the best cutters need to avoid such stones, and do.

Plenty of people purchase 1 ct ECs that face up as large as a 0.75 ct EC. It took me forever to find an EC that isn't only a good performer but faces up correctly for its carat weight. A 1 ct EC (supposing a generic ratio) should measure 7 x 5 mm but almost all the 1 ct ECs I looked at both online (in stock and dropshippers) and at B&M stores are closer to 6 x 4 mm which is a 0.75 ct EC measures. When I was shopping for a potential upgrade to a 1.5 ct EC, almost all of them measure at 7 x 5 mm which is the same size as my 1 ct EC. Therefore, there was absolutely no incentive for me to pay more for a stone that is the same size as my current stone.

Excellent point Chrono!!
I think we get a bit spoiled when we can search so effectively online- both consumers and dealers alike.
I used to be out on the road, and in jewelry stores- the "broader" retail jewelry environment, and considering that, you're surely right.
To correct what I wrote: it's pretty tough to sell a 1ct stone that looks like .75ct to consumers who have educated themselves online.

 

[Karl_K]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

This is my classification and not accepted industry wide for ECs

Classic:
large table(70% or so), fairly flat crown. Well cut they are bright with nice patterns mostly large flashes and not a lot of med. and small flashes except around the corners.

Modern:
Higher crown, smaller tables(under 65%). Cut well they have more med. and small flashes than the classic style and overall more life. They too should have pleasing patterns in diffused lighting but in direct or mixed lighting will have more flashes of light both white and colored(fire) than the classic style.
In diamond geek terms they have more scintillation events for any given movement.

There are people who love one type over the other and some who love both.

 

[Rockdiamond]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

In my experience, looking only at table depth- even CA/PA overlooks a crucial aspect- corner size. The size of the triangles created by the corners is a vital element in an Emerald Cut's appearance in terms of glitter ( sparkle) liveliness- whatever we want to call it..
I'd even say greater than table/depth.

 

[Lula]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

Great topic Lula!! Thanks, David
I think that there's so much misunderstanding of how and why a diamond looks as it does.
There's a common thread here at PS- some diamonds are cut for weight, others for light performance.
In fact, financial performance has to be paramount.
EVERY diamond is cut considering weight retention. If a cutter ignores this aspect, they won't be a cutter long. This makes sense to me
The process might be: Well, we can cut a round which sells for this amount, or a radiant that sells for this amount.
Even specialized cutters need to pay attention to whats left after they've polished- even if they're cutting for excellence in cut.
They can sell a "super ideal" 1.00 for more than a "regular" GIA triple EX weighing 1.10cts- bottom line is the bottom line.
There's a balance between weight retention, beauty and saleability. This is exactly what I'm trying to get at with this thread -- how do cutters balance these; which gets thrown to the curb first? It seems counter-intuitive to put beauty behind weight retention (wouldn't beauty sell faster and command a higher price?), but I think all of us on PS who've been frustrated by the stock offered in most local jewelry stores see the sacrifice of beauty for weight. Many consumers buy weight over beauty, too
To say that diamonds are seldom cut for light performance is too broad a statement IMO. It really depends where one is looking, what shapes, so many factors.
If we use the pool of diamonds that are actually listed with pics online, as many people reading this will do, I don't feel it's accurate to say that cutters are not concerned with how the stone looks. I have to disagree -- there are some amazing dogs out there; how a cutter could not "notice" the lack of appeal of some of what's out there is beyond me.
"Light performance"= personal preference. Agree to a point. PS could definitely be more tolerant of well-cut stones of different "flavors."

I've had the experience of looking through thousands of stones of a cutters stock- and it's easy to see stones where the balance was tipped to far in the direction of weight retention. I find a similar experience when I see a really badly cut stone photographed and shown online,
I agree that more emerald cuts will fall into this category compared to other shapes. Having said that- it's pretty tough to sell a 1ct stone that looks like .75cts......I'm sure someone buys them....but IME the best cutters need to avoid such stones, and do. It's been my experience that this is common -- the majority of the ECs available are deep.


People are talking about "branded emerald Cuts"- I am not familiar with any branded EC's - which does not mean they don't exist, but I've not seen them advertised. Once additional facets are added on- such a Tycoon, I don't believe GIA will classify the stone as an Emerald cut- but I'm not positive about that particular cut. The extra facets take it out of EC range for me, too; I think most people looking for traditional emerald cuts would not seek out stones with extra facets -- changes the look too much.

One of the things I love the most about emerald cuts is the fact that there's so much variation. Moving- or adding- facet breaks on the pavilion can give the stone a super "steppy" look even though "the numbers" may not be there.
For example, crown height- sometimes creative use of facet breaks makes a shallower stone look like a deeper one- and shallow is sometimes good at preserving more spread. But shallow cut may come with its own set of problems, right?
This is one of the main reasons that even if one knows CH/PA, it won't allow classifications as we do with rounds ( HCA ie)
In other words, higher crown small table will NOT always equal better cut than large table lower crown. Agreed. I've seen many examples of beautiful EC stones on this forum that break every "numbers" rule. But I do think that this is where personal preference comes in -- just like with rounds, if a person prefers a smaller table, he/she is probably not going to be attracted to diamonds with larger tables. Even people who don't know a thing about diamond cut and percentages can express a preference for one "flavor" of a RB over another, when given a choice between several diamonds. The problem with ECs is there are many more poorly-cut stones than there are well-cut stones, so it often feels like the choice is between so-so, bad, and worse. There are very few "best" options to compare.

Makes life more interesting yes? Ha-ha, for those of us that like puzzles, yes!

 

[Lula]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

Having said that- it's pretty tough to sell a 1ct stone that looks like .75cts......I'm sure someone buys them....but IME the best cutters need to avoid such stones, and do.

Plenty of people purchase 1 ct ECs that face up as large as a 0.75 ct EC. It took me forever to find an EC that isn't only a good performer but faces up correctly for its carat weight. A 1 ct EC (supposing a generic ratio) should measure 7 x 5 mm but almost all the 1 ct ECs I looked at both online (in stock and dropshippers) and at B&M stores are closer to 6 x 4 mm which is a 0.75 ct EC measures. When I was shopping for a potential upgrade to a 1.5 ct EC, almost all of them measure at 7 x 5 mm which is the same size as my 1 ct EC. Therefore, there was absolutely no incentive for me to pay more for a stone that is the same size as my current stone.

Excellent point Chrono!!
I think we get a bit spoiled when we can search so effectively online- both consumers and dealers alike.
I used to be out on the road, and in jewelry stores- the "broader" retail jewelry environment, and considering that, you're surely right.
To correct what I wrote: it's pretty tough to sell a 1ct stone that looks like .75ct to consumers who have educated themselves online.

And add to this the problem of the average consumer buying diamonds based on weight, having no idea that two stones of the same carat weight can be vastly different in face-up size. The majority of ECs also seem to have thick or very thick girdles, which makes the search for a one-carat stone that faces up like a one-carat stone even more of a challenge. I wish I could sort online inventory by girdle thickness!

 

[Lula]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

This is my classification and not accepted industry wide for ECs

Classic:
large table(70% or so), fairly flat crown. Well cut they are bright with nice patterns mostly large flashes and not a lot of med. and small flashes except around the corners.

Modern:
Higher crown, smaller tables(under 65%). Cut well they have more med. and small flashes than the classic style and overall more life. They too should have pleasing patterns in diffused lighting but in direct or mixed lighting will have more flashes of light both white and colored(fire) than the classic style.
In diamond geek terms they have more scintillation events for any given movement.

There are people who love one type over the other and some who love both.

Thank you, Karl -- this is exactly what I was referring to earlier. I think these two types (noting that these are Karl K.'s classifications and not accepted industry-wide) could be useful in EC discussions on PS. Those of us (me) who like the classic style probably wouldn't kick a well-cut modern style out of bed, but visually *prefer* the long clean lines of the classic cut. Photos of well-cut examples and a list of differences between the two types would be helpful. For example, I like the look of a larger table because I feel like it allows me to see into the diamond more clearly. I know that that preference comes with more table glare and possibly less fire -- especially in a poorly-cut classic cut. Chrono is really good at explaining how table size affects the appearance of the stone. I guess my question is, if a consumer prefers a classic cut, what's the best way to advise the consumer on how to pick a well-cut example of that type? My assumption has been that what we look for in the ASET and IS images is the same across the two types, right? I'm asking because I think I remember reading a comment by Karl in some thread that a lot of red in an EC ASET could be an indication of a lower crown height, which might be an indication that the stone is a decent classic cut -- I think I'm talking in circles, so I'll stop now

 

[Lula]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

In my experience, looking only at table depth- even CA/PA overlooks a crucial aspect- corner size. The size of the triangles created by the corners is a vital element in an Emerald Cut's appearance in terms of glitter ( sparkle) liveliness- whatever we want to call it..
I'd even say greater than table/depth.

Yes, the vast majority of ECs I see (in stores and online) seem to be cut with very small corners. Why? To save weight? If so, that, to me, would be another indication that when it comes to ECs, cutters typically put weight over beauty and performance (sparkle).

 

[Karl_K]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

Yes, the vast majority of ECs I see (in stores and online) seem to be cut with very small corners. Why? To save weight?

Yes mainly to save weight, but there are people that prefer them that way.

 

[Karl_K]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

I could spend days writing about the difference but the vast majority of people would go.. huh?
It is very hard to describe in words but seeing well cut samples side by side it is very easy to see.

 

[chrono]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

In my experience, looking only at table depth- even CA/PA overlooks a crucial aspect- corner size. The size of the triangles created by the corners is a vital element in an Emerald Cut's appearance in terms of glitter ( sparkle) liveliness- whatever we want to call it. I'd even say greater than table/depth.

Can I trouble Karl or anyone else to do a computer graphic predictor of large shoulders versus skinny shoulders for sparkliness?

 

[chrono]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

Lula,

Even in the world of round diamonds, many consumers (outside of PS) are buying stones that are cut for weight, not beauty. This is because this "tradition" has stuck since education about cut isn't easy to find and absorb. Imagine how much worse it is for fancy shapes! In the newer and upcoming Asian market, cut quality is greately desired by a huge portion of the market so the trade has no choice but to cater to this. I hope that one day, cut quality will be given more emphasis by the general public and well cut stones can be more easily found at most vendors.

I, too, am interested in find out the cons of a shallow EC. I agree that it takes more than a high crown + small table to look great. It is no guarantee that it will look prettier than a low crown + large table stone. Lula, I definitely share you pain when shopping for ECs, it feels like my options are to pick the least ugly of the lot, making the best of my final selection.

 

[Rockdiamond]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

snip.....

But shallow cut may come with its own set of problems, right?

snip.....

Bingo- what a great question!!

NO- there's nothing inherently "wrong" with a shallower diamond just like there's nothign inherently "right" about a small table high crown diamond.
This is why formulas do not work.

Lula- love this thread.
It's honestly helped to broaden my perspective.
I'm totally spoiled when it comes to looking at stones, due to the manner in which I do it.
Clearly I've not taken enough time to look over the newly expanded listings with pics available to consumers online.
Chrono- thanks in that regard too- I'm sure your experiences as a retail consumer are very much indicative of what others must be experiencing.

 

[Lula]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

I could spend days writing about the difference but the vast majority of people would go.. huh?
It is very hard to describe in words but seeing well cut samples side by side it is very easy to see.

Yes, the more ECs I've seen in person, the more I am able to apply the information in your p3 article to "real life" examples. But it's hard to find stores that carry enough ECs to make side-by-side comparisons meaningful. Most mainstream jewelry stores stock only one or two ECs! I have had better luck at pawn and second-hand shops.

 

[Lula]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

In my experience, looking only at table depth- even CA/PA overlooks a crucial aspect- corner size. The size of the triangles created by the corners is a vital element in an Emerald Cut's appearance in terms of glitter ( sparkle) liveliness- whatever we want to call it. I'd even say greater than table/depth.

Can I trouble Karl or anyone else to do a computer graphic predictor of large shoulders versus skinny shoulders for sparkliness?

This would be helpful -- pretty-please-with sugar-on-it, Karl or someone?

 

[Lula]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

Lula,

Even in the world of round diamonds, many consumers (outside of PS) are buying stones that are cut for weight, not beauty. This is because this "tradition" has stuck since education about cut isn't easy to find and absorb. Imagine how much worse it is for fancy shapes! In the newer and upcoming Asian market, cut quality is greately desired by a huge portion of the market so the trade has no choice but to cater to this. I hope that one day, cut quality will be given more emphasis by the general public and well cut stones can be more easily found at most vendors.I agree with you on all points. How...the whole story, especially with fancies [/b]

I, too, am interested in find out the cons of a shallow EC. I agree that it takes more than a high crown + small table to look great. It is no guarantee that it will look prettier than a low crown + large table stone. Lula, I definitely share you pain when shopping for ECs, it feels like my options are to pick the least ugly of the lot, making the best of my final selection. I am prepared to keep looking until I find the right one, but I have to admit it's much harder to find a good EC, in my price and size range, than I ever expected, and the sheer number of "meh" ECs out there is mind-numbing! I certainly believe David and other vendors on here who say that they look at dozens and dozens of stones before finding one or two keepers. Think about this, though -- the stones they reject end up in other stores, virtual or bricks-and-mortar -- where consumer like us have to devise our own sorting methods, without the benefit of viewing dozens and dozens of stones to train our eyes. Most vendors set limits on how many stones can be called in, or charge a fee, and it gets expensive. That's why I think assembling our combined experiences in evaluating ECs may be helpful to others. For example, one of the first things a consumer should think about is the type of EC they prefer -- I prefer classic. But if a vendor I'm working with prefers modern, and calls in 3 modern style stones for me to view, I may not like any of them. Or I may believe that's all that's available and so I'll choose the best among the three, even though they're not really my type of EC. Same thing with corners -- Karl stated that some people prefer smaller-cornered ECs; some prefer larger corners. These sorts of physical preferences -- corner size, table size, L/W ratio, should be determined first; the next step would be to find three stones that meet those physical preferences, and asses each of the three for cut quality, sparkle, personality. Maybe this is too optimistic, as the number of ECs is so small, customers might have to be more flexible on things like corner size and table size -- I don't know the answers to these questions; I'm just putting this out there for discussion.

 

[Lula]

Re: Role of Leakage & Obstruction in Step-cut Facet Patterns

snip.....

But shallow cut may come with its own set of problems, right?

snip.....

Bingo- what a great question!!

NO- there's nothing inherently "wrong" with a shallower diamond just like there's nothign inherently "right" about a small table high crown diamond. Shallow stones do seem to have a different "look" to them than deeper stones -- at least in my small sample -- especially when combined with large corners
This is why formulas do not work.Agreed -- I think it's much more helpful to talk of specific visual characteristics -- like corner size -- rather than numbers

Lula- love this thread.
It's honestly helped to broaden my perspective. Thanks -- that's nice of you to say, David
I'm totally spoiled when it comes to looking at stones, due to the manner in which I do it.
Clearly I've not taken enough time to look over the newly expanded listings with pics available to consumers online. The pictures and videos help; but they don't tell the whole story either, as they are 2-D and we see the stones in 3-D, under lighting conditions that may be very different from the lighting conditions in the vendor's showroom or photo lab.
Chrono- thanks in that regard too- I'm sure your experiences as a retail consumer are very much indicative of what others must be experiencing.