How do you calculate EC cut grade?

[Wholovesskunks]

Do I have enough information from the GIA report to do it? I tried one particular tool and it asked for the crown angle which I don't have. Here are the specs!

 

[BlingDreams]

Check this link - https://www.pricescope.com/wiki/diamonds/diamond-grading-chart-emerald-radiant

You still need the crown height % though. That can be found on a Sarin report.

But keep in mind that numbers alone can't tell you if it's a great diamond, especially with step cuts. Do you have photos/videos/ASET's to share?

 

[BlingDreams]

Nooooooooooooo.... WAY too much light leakage! That's the white area, in case you didn't know. Here's a link you might find useful - http://beyond4cs.com/2014/12/aset-reference-charts/

And here's a good video to watch -

 

[Wholovesskunks]

Grrrrrrr.... I specifically asked about light leakage and they said ASET images are really hard on fancy cuts and that this had excellent light return and flashes. Back to the drawing board I go I guess. :/

 

[Wholovesskunks]

Do you think it's the machine? All the stones with a blueprint that are Ascher or emerald seem to have the white middle. :/

 

[BlingDreams]

Doubtful. Probably poorly cut diamonds. But you can ask when they last calibrated the machine and make sure it was done recently.

Ask them to make video for you to confirm the light return. Ask to see the diamond in regular light, spotlight, and dim light; they should have a lighting set up that can do that. You want to look at the "winking" of the facets and any repetitive dark areas.

ETA: Look at this search on 2.01ct I VS1 emerald cut diamonds and you'll see that other emerald cuts with similar specs are selling for $12-$13k on average. So, if their price is 9K, that's pretty reflective of the cut quality (usually).

 

[Wholovesskunks]

I don't understand why they classified it as an excellent cut. Like where it says, ideal, excellent, very good, good, and fair. Across the board for cut, symmetry, and polish it showed Excellent. Others showed other ratings. I realize GIA doesn't grade fancy shape cut but assumed this grade was made and assigned for some reason. Clearly I was wrong and excellent can mean poor. This is frustrating to say the least.

 

[Wholovesskunks]

Stats right from the listing. Cut clearly is shown as excellent.

 

[BlingDreams]

It is frustrating. And it's unfortunate that you're stuck using this other vendor (if I remember correctly from your post about the insurance issue) otherwise I'd send you straight to IDJewelry or Good Old Gold and have them search for you; they're awesome at stepcuts.

You might just have to reset your priorities. Do you care more about the carat, cut, or color (clarity is pretty much non-negotiable when it comes to stepcuts... you need VS2 or above to make sure it's eye clean)? If you care more about the finger coverage, you might be okay with the cut of this stone. But if you want something that really reflects the beautiful pastels and shows the steps, you'll need to keep looking.

 

[BlingDreams]

Emerald cuts (and other fancy cuts) aren't given a "cut" rating by GIA. That's a label B2CJewels (or some other vendor) put on it.

Do a search on here... there's a wealth of information about emerald cuts and cut quality, how to find a good one, etc.

 

[whitewave]

Just tell them you need more choices.

 

[Wholovesskunks]

Yes, I knew labs don't grade the fancy shapes for cut, I just wonder what criteria B2C used to label it the excellent rating. Color was my least important trait and cut and finger coverage were equal in weight. There was recently a post in here showing a deeper but more vivid EC and a much more shallow stone that lacked brilliance but was very unique and interesting looking and I liked the shallow cut one that was spread larger. Maybe that will be the case with this stone. I love everything about it including the ratio which is perfect to me. Just kinda bummed that the excellent cut appears to be a terrible cut.

 

[Wholovesskunks]

They didn't have any stones with the Blueprint besides this one in my price range. I asked. They couldn't get video on any of them either. I asked which one they thought to be the best option and they said hands down this one and I wouldn't be disappointed.

 

[BlingDreams]

They didn't have any stones with the Blueprint besides this one in my price range. I asked. They couldn't get video on any of them either. I asked which one they thought to be the best option and they said hands down this one and I wouldn't be disappointed.

What's their return policy? Maybe you could have them send it to you for inspection and then decide.

 

[Wholovesskunks]

I wonder why this emerald (and actually it looks Ascher to me) received a good cut rating.

http://www.b2cjewels.com/dd/1921857/2-14-carat-emerald-diamond-d-color-vs2-clarity

 

[diagem]

There is no cut grade for Emerald Cuts at GIA. The only information offered by GIA about the cut is if the symmetry features (facet sizes, shapes & junctions meeting points) were placed correctly and the facet surfaces are polished adequately.

I constantly see GIA Ex/Ex Emerald Cuts (and most other fancy shapes) which perform oppositely from their symmetry and polish grades and seeing plenty of fair/good grades perform and look amazing. The symmetry and polish grades of GIA fancy's are confusing at best.

 

[oldminer]

Use this look to the AGA/NAJA Cut grading/screening tool on Pricescope which has automated use of the chart you were initially given a link to. Without following the rules automated in the chart, you may not get reasonable results. Here is the correct link for the grader: https://www.pricescope.com/tools/AGA_NAJA_Cut_Class_Grader

 

[Wholovesskunks]

Use this look to the AGA/NAJA Cut grading/screening tool on Pricescope which has automated use of the chart you were initially given a link to. Without following the rules automated in the chart, you may not get reasonable results. Here is the correct link for the grader: https://www.pricescope.com/tools/AGA_NAJA_Cut_Class_Grader

That's the one that I need a crown angle for. How do I find that?

 

[Wholovesskunks]

There is no cut grade for Emerald Cuts at GIA. The only information offered by GIA about the cut is if the symmetry features (facet sizes, shapes & junctions meeting points) were placed correctly and the facet surfaces are polished adequately.

I constantly see GIA Ex/Ex Emerald Cuts (and most other fancy shapes) which perform oppositely from their symmetry and polish grades and seeing plenty of fair/good grades perform and look amazing. The symmetry and polish grades of GIA fancy's are confusing at best.

The cut label from B2C is not based on the GIA report. I say this because lots of B2C stones have a fair cut label with excellent and very good polish/symmetry on the GIA report. I'm trying to figure out how B2C determines the cut grade label. Not GIA. I know GIA isn't giving a cut grade.

 

[MollyMalone]

That's oldminer's (David Atlas') AGA/NAJA cut grading-screening tool one] that I need a crown angle for. How do I find that?

As ILikeShiny said, it's the crown height percentage (not angle) which you need to use that tool & GIA's reports for emerald cuts don't give you a crown height %, but Sarin reports for emerald cuts do.

But honestly, even tho' a Sarin report can fill in that blank, I agree with chrono, who has said here, more than once:

No formulae, no guarantees. There is no magic shortcut or guaranteed specifications or even a range, I'm afraid. I've seen all to many ECs with supposedly sweet numbers that were duds. It is all about how ALL the angles (not just table and depth percentages) work together, especially P1, P2 and P3 in the pavilion, which are never noted in the lab reports.

Also, personal preferences come into play. There is much variation in the faceting of emerald cuts & not everyone likes them all. For example, there is one in Good Old Gold's current in-house listings where the ASET is fine & a wholly detached viewer would see the video as cause for concern, but it's an EC I would not be happy with because I really don't like the "pattern."

Have you been able to examine a fair number of ECs in real life? Although they are more often seen in brick-and-mortar stores than used to be the case, they aren't a dime a dozen in local jewelers' display cases. Also, by any chance, do you live within convenient distance to NYC?

 

[Wholovesskunks]

Use this look to the AGA/NAJA Cut grading/screening tool on Pricescope which has automated use of the chart you were initially given a link to. Without following the rules automated in the chart, you may not get reasonable results. Here is the correct link for the grader: https://www.pricescope.com/tools/AGA_NAJA_Cut_Class_Grader

According to the calculator, with all other needed variables entered correctly, as long as the crown percent is somewhere between 9-17.2% it is between 2B and 1A. If it is below 9 or higher than 17.2 it could range from 3A to 4B. I just don't know how to compute that percent so I checked all of them that it could be.

 

[Wholovesskunks]

As ILikeShiny said, it's the crown height percentage (not angle) which you need to use that tool & GIA's reports for emerald cuts don't give you a crown height %, but Sarin reports for emerald cuts do.

But honestly, even tho' a Sarin report can fill in that blank, I agree with chrono, who has said here, more than once:

Also, personal preferences come into play. There is much variation in the faceting of emerald cuts & not everyone likes them all. For example, there is one in Good Old Gold's current in-house listings where the ASET is fine & a wholly detached viewer would see the video as cause for concern, but it's an EC I would not be happy with because I really don't like the "pattern."

Have you been able to examine a fair number of ECs in real life? Although they are more often seen in brick-and-mortar stores than used to be the case, they aren't a dime a dozen in local jewelers' display cases. Also, by any chance, do you live within convenient distance to NYC?

I truly haven't seen enough ECs. I just always loved the look. I'm down in rural Florida. Very few jewelers here and most don't have emeralds and if they do it's only a couple and they've always had visible inclusions rendering the stone not acceptable to me. That's why I've never ended up with one.

 

[Karl_K]

Cutting awesome EC cuts are very hard and they do not fit modern production methods very well. That makes them rare. You can not cut them to a strict formula unless you have a lot of near identical rough or are willing to live with poor yields.
Even then they are best when individually tuned with a combination of skill, scans and experienced eyes.
Change the L/W ratio, the corners or table size and it makes big changes in the angles and placement needed to get awesome results.
In today's large factories a well cut EC is a fluke more than anything else.
There are still a few smaller outfits that can do them well.

 

[MollyMalone]

I too love emerald cuts, have always been intrigued by the way they (if nicely cut) draw you in. Have you watched some of GOG's comparative videos of emerald cuts? That could be a good, next step to getting a better handle on what's well-cut and your personal aesthetics in ECs, so you could have a more informed conversation with B2C. But there really is no satisfactory substitute imo for seeing an EC in hand, so that's why B2C's generous return policy (including the fact that they pay for the insured, return shipping) is a big plus.

 

[Wholovesskunks]

I've been trying to push B2C a bit more for info on the stone. Here's what I got this morning.

11:06 AM
Krista
My biggest concern is why does there appear to be so much light leakage? Do you think it's a malfunction issue or the machine?

11:07 AM
Alex Johnson
I would like to inform you that Aset Ideal scope is basically used on round diamonds to check the light performance it is not use for fancy cut diamonds.

11:10 AM
Alex Johnson
Krista Aset and Ideal scope images were made to check the light performance for round diamonds however if we click that for fance diamonds the shapes are different so it we not give you complete information about light performance as if you check for round diamond facet are 57 and in fancy there are more than round and however if we click image it will show as leakage.

11:11 AM
Krista
So the gemologist does believe it has great light performance then?

11:13 AM
Alex Johnson
Yes our diamond partner gemologist gives comments on this diamond they informed us that it has excellent light performance also as it is an IF clarity diamond it gives more sparkle and fire performance.

 

[Karl_K]

ugh!!!!!! that cs rep needs to be sent back to school.

 

[oldminer]

The calculator tool does NOT require or ask for a crown angle on anything but round diamonds. Read carefully and you will see you are just not reading first. This is a screening tool, not a way to make a final choice. It is very true that cutters can make a very pretty diamond or a rather un-pretty stone with the same or close to the same measurements. However, when allowed the choice, a cutter will try to make a diamond beautiful rather than ugly. It makes better business sense especially now when so many consumers expect some kind of high range light return on their chosen diamond.

In spite of many naysayers, this system can help find a diamond that has less cutting faults than another and has a good chance of performing well with not only light return, but with apparent size for its weight. These are good things to help you find a better diamond.

When a seller tells you every fancy shape diamond they sell is "excellent" cut, they are testing you to see if you understand or if you have not done your homework. The ones who say no one can grade more than a couple fancy shape diamonds have their own agendas and may not be thinking of how to make things better instead of just encouraging the status quo. Any fancy which grades 2B or higher may have a good chance of becoming a great choice. There are far more which grade lower, 3A and down, that will have more serious defects in proportions or cut which will always remain a detriment to quality or apparent size. They may look fine, but not everything is fine with those.

Not every characteristic of a diamond improves or decreases light performance. Some characteristics improve or decrease durability, and/or visible size to weight ratio. Some do have effects on light return which can be predicted by proportions. This system can help you choose diamonds with more likelihood of having fewer issues and better looks.

 

[Karl_K]

I've been trying to push B2C a bit more for info on the stone. Here's what I got this morning.

11:06 AM
Krista
My biggest concern is why does there appear to be so much light leakage? Do you think it's a malfunction issue or the machine?

11:07 AM
Alex Johnson
I would like to inform you that Aset Ideal scope is basically used on round diamonds to check the light performance it is not use for fancy cut diamonds.

First off ASET and ideal scope are 2 different things and ASET is used on fancy cuts. No scope on any diamond will give the entire picture but can be used to find major issues

11:10 AM
Alex Johnson
Krista Aset and Ideal scope images were made to check the light performance for round diamonds however if we click that for fance diamonds the shapes are different so it we not give you complete information about light performance as if you check for round diamond facet are 57 and in fancy there are more than round and however if we click image it will show as leakage.

Huh that makes no sense.

11:11 AM
Krista
So the gemologist does believe it has great light performance then?

11:13 AM
Alex Johnson
Yes our diamond partner gemologist gives comments on this diamond they informed us that it has excellent light performance also as it is an IF clarity diamond it gives more sparkle and fire performance.

"as it is an IF clarity diamond it gives more sparkle and fire performance."
Someone toss me a shovel its getting really deep in here!

 

[Wholovesskunks]

The calculator tool does NOT require or ask for a crown angle on anything but round diamonds. Read carefully and you will see you are just not reading first. This is a screening tool, not a way to make a final choice. It is very true that cutters can make a very pretty diamond or a rather un-pretty stone with the same or close to the same measurements. However, when allowed the choice, a cutter will try to make a diamond beautiful rather than ugly. It makes better business sense especially now when so many consumers expect some kind of high range light return on their chosen diamond.

In spite of many naysayers, this system can help find a diamond that has less cutting faults than another and has a good chance of performing well with not only light return, but with apparent size for its weight. These are good things to help you find a better diamond.

When a seller tells you every fancy shape diamond they sell is "excellent" cut, they are testing you to see if you understand or if you have not done your homework. The ones who say no one can grade more than a couple fancy shape diamonds have their own agendas and may not be thinking of how to make things better instead of just encouraging the status quo. Any fancy which grades 2B or higher may have a good chance of becoming a great choice. There are far more which grade lower, 3A and down, that will have more serious defects in proportions or cut which will always remain a detriment to quality or apparent size. They may look fine, but not everything is fine with those.

Not every characteristic of a diamond improves or decreases light performance. Some characteristics improve or decrease durability, and/or visible size to weight ratio. Some do have effects on light return which can be predicted by proportions. This system can help you choose diamonds with more likelihood of having fewer issues and better looks.

I did read. It asks for a crown height percentage not angle. That was a typo on my part. The crown height percentage is required for the tool. The seller did not say every fancy shape diamond they sell is excellent. They aren't. There are many EC's that are listed as very good, good, and fair. That is why I'm trying to understand why this stone is labeled as excellent cut by them. According to the tool, as long as the crown height percent, which I don't know right now, is between 9-17.2% it could have a grade from 1A-2B. Of course the crown height could be lower or higher and that would give it a lower grade.

 

[Wholovesskunks]

"as it is an IF clarity diamond it gives more sparkle and fire performance."
Someone toss me a shovel its getting really deep in here!

Isn't this scary? How is someone who doesn't understand or is new to all of this make an informed decision if they are receiving incorrect info from the reps? I went through B2C because they seemed to be knowledgeable and had great reviews. I'm glad there is a 30 day return policy. My fingers are crossed that it is beautiful in real life but if not it will go back.