shape
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Have I purchased a badly cut diamond?

bananahead

Rough_Rock
Joined
Jul 27, 2021
Messages
19
Hello . This is my first time on this forum and I would like to take you advice on a diamond I am in the processes of purchasing
It
1.01 e grade diamond with triple excellent grading from GIA certificate

table 60
Depth 61
Crown angle 33
Pavilion angle 41.8

attached screenshot of certificate dimensions

I have been reading up on angle cuts and I’m worried I have purchased a bad , dull diamond with these angle degrees? 120344BC-0F43-4B25-BA19-C132AF5DDD88.jpeg
 

jp201845

Brilliant_Rock
Joined
Jun 24, 2018
Messages
534
This type of diamond is known as a 60/60, and looking at the proportions unfortunately it’s not cut very well so this would be a pass for me. The most critical angle is the Pavillion and looking at your report at 41.8 it’s not in the recommended range. This diamond will definitely have light leakage and not perform very well.
 

yssie

Super_Ideal_Rock
Premium
Joined
Aug 14, 2009
Messages
23,060
Are you in a position to return? There is definitely some wiggle room with regard to proportions but... 41.8 pav combined with 80 lower halves, even accounting for rounding, that’s going to allow too much light to escape under the table.
 

DejaWiz

Brilliant_Rock
Joined
Apr 23, 2021
Messages
912
As other have mentioned, I would recommend that these proportions (especially the pavilion angle) be avoided.

The report is dated September 2019, so there may be a reason why this one has been lingering about for almost two years.



Here is some further reading about light leakage:

 

bananahead

Rough_Rock
Joined
Jul 27, 2021
Messages
19
Are you in a position to return? There is definitely some wiggle room with regard to proportions but... 41.8 pav combined with 80 lower halves, even accounting for rounding, that’s going to allow too much light to escape under the table.

Sorry for the delay in replying . The diamond is being set in the ring and I’m to collect it on Friday ! What would be the perfect size for a beautiful diamond ? I had especially chosen the triple Excellent as I thought this would make it a good diamond but I’m learning fast it isn’t the case.. should I avoid 60/60 and never go as far up as 41? I wonder what they will charge me to change the diamond to another?
 

lovedogs

Super_Ideal_Rock
Premium
Joined
Jul 31, 2014
Messages
14,111
As other have mentioned, I would recommend that these proportions (especially the pavilion angle) be avoided.

The report is dated September 2019, so there may be a reason why this one has been lingering about for almost two years.



Here is some further reading about light leakage:


I agree.
 

bananahead

Rough_Rock
Joined
Jul 27, 2021
Messages
19
Shall I avoid 60/60 diamonds and not go as far as 41?.. I don’t know how I stand with regards to stopping the setting of the stone in the ring now and choosing another ? I can but try as I have exchanged my old diamond plus put £1000 extra deposit down on it so don’t want to lose that on top of everything else
 

lovedogs

Super_Ideal_Rock
Premium
Joined
Jul 31, 2014
Messages
14,111
Shall I avoid 60/60 diamonds and not go as far as 41?.. I don’t know how I stand with regards to stopping the setting of the stone in the ring now and choosing another ? I can but try as I have exchanged my old diamond plus put £1000 extra deposit down on it so don’t want to lose that on top of everything else

There is a very helpful chart by Gary floating around which will help you figure out ideal proportions. I'll try to find it and paste it here
 

lovedogs

Super_Ideal_Rock
Premium
Joined
Jul 31, 2014
Messages
14,111
I cant paste it bc it's the wrong format to attach. But at the bottom of this thread Gary attached the most updated version of the chart.

You want to stick with stones that fall in the ranges in the green column or the 2 next to the green column.

 

bananahead

Rough_Rock
Joined
Jul 27, 2021
Messages
19
Thank you I will take a look ..the shop is closed today so I’ve left a voicemail message for the jeweller to contact me before going any further as I have issues . Let’s hope he isn’t to miffed and we can work something out to a happy conclusion
 

DejaWiz

Brilliant_Rock
Joined
Apr 23, 2021
Messages
912
Shall I avoid 60/60 diamonds and not go as far as 41?.. I don’t know how I stand with regards to stopping the setting of the stone in the ring now and choosing another ? I can but try as I have exchanged my old diamond plus put £1000 extra deposit down on it so don’t want to lose that on top of everything else

Here is the education page with the recommended proportion ranges:

 

sledge

Ideal_Rock
Premium
Joined
Apr 23, 2018
Messages
5,219
For a ring I would limit the proportions to the following:

54-57 table
60-62.4 depth
34-35 crown
40.6-41 pavilion
75-80 LGF
GIA or AGS only

In addition you want COMPLIMENTARY angles. What this means is shallow crown combined with a steep pavilion, or vice versa. For instance, 34/41 may work but 35/41 not so much. Just as 35/40.6 works better than a 34/40.6. A 34.5 can pair nicely with 40.8 but can sometimes work with a 40.6 and 41.

You have to wrap your head around the fact it’s not about one proportion but rather all them working in unison with each other. Then there is a factor of precision cutting and averages at play that make evaluating proportions only a dangerous game. Pictures, videos or advanced images really help confirm performance.

Although it may sound small a 0.2 degree change in pavilion can make a big difference in overall light performance.

I would definitely trade/return and find a stone with more promising proportions. As you are learning GIA 3X is a very broad “scoring” system and not all them meet the criteria for the cream of the crop in regards to performance. You can narrow using parameters but post back so we can help you further interpret and evaluate.

What is your budget for the diamond only? We may be able to find you a better alternate.
 

DejaWiz

Brilliant_Rock
Joined
Apr 23, 2021
Messages
912
60/60 can be just fine but just not this one. There's your forecasted ASET based on the numbers. 33418.jpg


This is awesome...thank you, Jon!
 

DejaWiz

Brilliant_Rock
Joined
Apr 23, 2021
Messages
912
For a ring I would limit the proportions to the following:

54-57 table
60-62.4 depth
34-35 crown
40.6-41 pavilion
75-80 LGF
GIA or AGS only

In addition you want COMPLIMENTARY angles. What this means is shallow crown combined with a steep pavilion, or vice versa. For instance, 34/41 may work but 35/41 not so much. Just as 35/40.6 works better than a 34/40.6. A 34.5 can pair nicely with 40.8 but can sometimes work with a 40.6 and 41.

You have to wrap your head around the fact it’s not about one proportion but rather all them working in unison with each other. Then there is a factor of precision cutting and averages at play that make evaluating proportions only a dangerous game. Pictures, videos or advanced images really help confirm performance.

Although it may sound small a 0.2 degree change in pavilion can make a big difference in overall light performance.

I would definitely trade/return and find a stone with more promising proportions. As you are learning GIA 3X is a very broad “scoring” system and not all them meet the criteria for the cream of the crop in regards to performance. You can narrow using parameters but post back so we can help you further interpret and evaluate.

What is your budget for the diamond only? We may be able to find you a better alternate.

Ya know, the more I read your wonderfully descriptive posts, the more that I am inclined to start searching for and recommending AGS000 diamonds for those wanting natural grown.

GIA is just too loose for prosumer needs.

Who know? Maybe the more AGS000 diamonds get recommended and sold, then perhaps AGS diamonds will start to appear more frequently.
 

lovedogs

Super_Ideal_Rock
Premium
Joined
Jul 31, 2014
Messages
14,111
Ya know, the more I read your wonderfully descriptive posts, the more that I am inclined to start searching for and recommending AGS000 diamonds for those wanting natural grown.

GIA is just too loose for prosumer needs.


Who know? Maybe the more AGS000 diamonds get recommended and sold, then perhaps AGS diamonds will start to appear more frequently.

Many of us primarily advise folks to stick to AGS000 if possible, but with the help of prosumers here, GIA stones in strict ranges with videos can be properly vetted. @flyingpig (as an example) can "read" photos better than almost anyone I've seen (excluding those in the trade), and can spot leakage very well even without an ASET/IS.
 

oncrutchesrightnow

Brilliant_Rock
Joined
Apr 17, 2006
Messages
807
Question to experts and old timers: why does no one ask for advice on 60/60s these days?
 

bananahead

Rough_Rock
Joined
Jul 27, 2021
Messages
19
Thank you to everyone for your kind help with this . It has been very informative. I’m hoping that the jeweller will be calling me today and that we can together get this sorted . I have paid £11,000 for the ring so I need it to be perfect for me ..
 

bananahead

Rough_Rock
Joined
Jul 27, 2021
Messages
19
Thank you to everyone for your kind help with this . It has been very informative. I’m hoping that the jeweller will be calling me today and that together we can get this sorted. I have paid £11,000 for the ring so I need it to be perfect for me
 

Snowdrop13

Ideal_Rock
Premium
Joined
Aug 27, 2011
Messages
2,631
You must be in the U.K.? Honestly, this thread makes me mad on your behalf, the way jewellers do not try to educate customers and over emphasise colour and clarity without mentioning cut. Did you really want/need an E colour?

Just for info, you could get a superideal cut for similar money,


please try to get your money back!
 

jp201845

Brilliant_Rock
Joined
Jun 24, 2018
Messages
534
Only a handful of vendors sell super ideal diamonds and they have the advanced images to prove they are the best and have amazing light performance. Unfortunately brick and motor stores will tell you they have the best diamonds and unless you do your research and educate yourself they have no problem selling you a diamond with bad light performance.
 

bananahead

Rough_Rock
Joined
Jul 27, 2021
Messages
19
I’ve spoken to the jeweller and apparently they are booking me in with their gemologist at 11am tomorrow.. let’s hope he isn’t just another of their salesmen? .. I’ve told him to also have three or four alternative diamonds available to view with all there certifications too.. so I’m looking for the below

Table 54-57
Depth 60-62.4
Crown angle 34-35
Pavilion angle 40.6-41
LGF 75-80
Crown 15

3 c excellent ?

Is it a case of if one angle is wrong or not as the above then all other degrees are out or as long as I stick between these margins then the numbers will all add up?

What should I be looking to pay in UK Stirling for the diamond taking into account it is going into a platinum ring which has channel stones already in it

Thank you so much everyone for helping like this .. it’s a minefield out there ☹️
 

DejaWiz

Brilliant_Rock
Joined
Apr 23, 2021
Messages
912
I’ve spoken to the jeweller and apparently they are booking me in with their gemologist at 11am tomorrow.. let’s hope he isn’t just another of their salesmen? .. I’ve told him to also have three or four alternative diamonds available to view with all there certifications too.. so I’m looking for the below

Table 54-57
Depth 60-62.4
Crown angle 34-35
Pavilion angle 40.6-41
LGF 75-80
Crown 15

3 c excellent ?

Is it a case of if one angle is wrong or not as the above then all other degrees are out or as long as I stick between these margins then the numbers will all add up?

What should I be looking to pay in UK Stirling for the diamond taking into account it is going into a platinum ring which has channel stones already in it

Thank you so much everyone for helping like this .. it’s a minefield out there ☹️

All of the proportions must work in harmony together. If one of them is off, even slightly, then it can (and most likely will) mess up proper light reflection within and light return back out of the diamond.

There is a bit of leeway...

For example, if you are looking at a diamond with a 40.6° PA, a table width of 55-57%, a star facet size of 50-55%, and an LGD of 76-78%, then a CA up to 35.5° (maybe even 36.0°) will probably be just fine. You will have to visually judge it in a variety of lighting conditions to determine whether or not it speaks to you. Advanced images will also be of massive benefit, if they can get them for you.

Glad to hear that you are already wary of their gemologist being "just another salesperson", because they can have two positions:
1. Their affinity to their education
2. Their affinity to their store sales to push what is in their vault

Do NOT let them persuade you to buy a diamond with an "almost there" set of measurements and proportions. Patience is the key virtue, here. If they don't have a diamond that meets your criteria today, then there will be a handful that do in the near future, and you will be better off for exerting that patience. Thousands of diamonds get cut and polished every week and ready to ship to dealers, all over the world.

It's your money that they are trying to put into their cash register, so you should demand and get the absolute best. Always.
You are in control, not them...and sometimes they need a gentle reminder of that fact, because they have plenty of competition all over the planet that will happily get/ship you exactly what you want.

Here is the educational page with both the PriceScope and prosumer recommended proportion ranges:

 
Last edited:

sledge

Ideal_Rock
Premium
Joined
Apr 23, 2018
Messages
5,219
I am closing on a house in a different state today and traveling so I will have limited contact.

Best advice is stay in the ranges I mentioned earlier. If they give you something outside take a picture of the proportions and we can analyze further.

I’m sweet on 34.5/40.8 or 35/40.6 (with 43 pavilion depth, not 42.5 depth). Also 54-57 table and 61-62 depth. Both with 75-80 LGF but prefer 76-78 actuals (will be hard to gauge unless you’ve done some research, also table size and pavilion play into that).

Those are much tighter than the original range I gave you but what I would prefer to find if spending my bucks.

Other combos can work. In all cases I would tell the jeweler you want to think about it and post back here for more analysis.
 

bananahead

Rough_Rock
Joined
Jul 27, 2021
Messages
19
I am closing on a house in a different state today and traveling so I will have limited contact.

Best advice is stay in the ranges I mentioned earlier. If they give you something outside take a picture of the proportions and we can analyze further.

I’m sweet on 34.5/40.8 or 35/40.6 (with 43 pavilion depth, not 42.5 depth). Also 54-57 table and 61-62 depth. Both with 75-80 LGF but prefer 76-78 actuals (will be hard to gauge unless you’ve done some research, also table size and pavilion play into that).

Those are much tighter than the original range I gave you but what I would prefer to find if spending my bucks.

Other combos can work. In all cases I would tell the jeweler you want to think about it and post back here for more analysis.

I am closing on a house in a different state today and traveling so I will have limited contact.

Best advice is stay in the ranges I mentioned earlier. If they give you something outside take a picture of the proportions and we can analyze further.

I’m sweet on 34.5/40.8 or 35/40.6 (with 43 pavilion depth, not 42.5 depth). Also 54-57 table and 61-62 depth. Both with 75-80 LGF but prefer 76-78 actuals (will be hard to gauge unless you’ve done some research, also table size and pavilion play into that).

Those are much tighter than the original range I gave you but what I would prefer to find if spending my bucks.

Other combos can work. In all cases I would tell the jeweler you want to think about it and post back here for more analysis.

I am closing on a house in a different state today and traveling so I will have limited contact.

Best advice is stay in the ranges I mentioned earlier. If they give you something outside take a picture of the proportions and we can analyze further.

I’m sweet on 34.5/40.8 or 35/40.6 (with 43 pavilion depth, not 42.5 depth). Also 54-57 table and 61-62 depth. Both with 75-80 LGF but prefer 76-78 actuals (will be hard to gauge unless you’ve done some research, also table size and pavilion play into that).

Those are much tighter than the original range I gave you but what I would prefer to find if spending my bucks.

Other combos can work. In all cases I would tell the jeweler you want to think about it and post back here for more analysis.

Yes I will . I must say I am very nervous as I’m trying to get as much knowledge of the cuts and I don’t want to get it wrong again . I’m sure I will be fine

This is a ring they have suggested would be better ? I haven’t purchased it yet as wanted to ask everyone’s opinion first

ACADE61F-EC8F-49E4-849C-42668EFAE821.jpeg BDFC1A2D-25B7-45FE-9C17-42F58AF6A430.jpeg 5324371F-20CC-4D33-802A-40F0E9D723D3.jpeg B77D8A51-7212-493E-A8BD-842E663E2198.jpeg 08A92F28-9DB9-4C38-9F9A-B0F5A20338AF.jpeg
 
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