Excellent Diamond Proportions

[Sparkles4Luv]

Hello~I'm thinking I might upgrade the 0.70ct center stone in my e-ring to a 1.0ct stone or close to it--maybe 0.95 or so to keep the price down a bit. But what are the dimensions stone this size should have on average? Where can I find what a good depth percentage, diameter%, table%, crown height%, etc? Also, what are the normal dimensions of a 3/4 ct vs a 1ct?? I know every diamond is different but are there average measurements that should be kept in mind when buying a diamond?

My fiance and I bought the first diamond without knowing too much just based on clarity and color and it's great. But we'd like to make sure this next diamond is exceptionally proportioned since it will be with us forever!!! We've looked on various websites, but the 4Cs seems to be the emphasis and not too much detail on specifc measurements. We're fairly new at this..any guidance or a boost in the right direction would be appreciated!

Thanks!!!

 

[Ellen]

Hi sparkles,

Here's some numbers/specs to try and stick with.



Table 54-58

Depth 60-62

Girdle -Thin, Med., Slightly Thick, or a combination of those. i.e. Thin to Med.

Cut Grade - Very Good to Excellent/Ideal

Polish - Very Good to Excellent

Symmetry - Very Good to Excellent

Culet - None, Pointed, Very Small

Crown Angle - 34 - 35

Pavillion Angle 40.6 - 41

Fluorescence - A stone might possess anything fropm none/negligable to Very Strong. There's nothing wrong with this, many people like it. The only time it may cause a problem, is if it is very strong. On rare ocassions, it will cause the stone to appear milky/cloudy/oily in direct sun. If you find one with med. or strong, it will lower the price some.


If you are shopping locally, I would recommend sticking with GIA and AGS graded stones. And run them through the HCA. Ideally you want the x to fall within the overlap area of AGS/GIA, or close to. You just plug the numbers in, and see where it lands.

https://www.pricescope.com/cutadviser.asp


If you just stick to AGS0 stones, which are graded for light performance (you want a zero for that), it will take a lot of pressure off you, and you should end up with a decent stone.

Hope this helped, and happy shopping!

 

[diamondseeker2006]

I would agree with Ellen but restrict the cut grade to Excellent and Ideal. If you don''t, it will be like sifting through a needle in a haystack to find a great stone. It will be a lot less frustrating to limit your search to excellent cut. Use this search tool and put in excellent-excellent for cut and check GIA and AGS only for labs.

https://www.pricescope.com/sift.aspx

 

[Sparkles4Luv]

Thank you for all the info...so here is an example of my stone right now and from what I see I think the girdle is way too thick which I'm not sure how if affects the overall brilliance of the ring..how do you think this stone rates overall in quality and what would you think in regards to price?

0.70ct Round brilliant, SI 1, F Color

Depth % 63.9
Diameter % 64.1
Crown Height % 13.4
Pavillion Depth % 43.4
Girdle Thickness: Thick to very thick
Culet Size: None
Polish: Good
Symmetry: Good
Fluorescence: Faint Blue
Dimensions: 5.44-5.47 x 3.49 MM

(Diamond Report is from IGI)

 

[Lorelei]

Date: 3/14/2008 11:17:25 AM
Author: Sparkles4Luv
Thank you for all the info...so here is an example of my stone right now and from what I see I think the girdle is way too thick which I'm not sure how if affects the overall brilliance of the ring..how do you think this stone rates overall in quality and what would you think in regards to price?

0.70ct Round brilliant, SI 1, F Color

Depth % 63.9
Diameter % 64.1
Crown Height % 13.4
Pavillion Depth % 43.4
Girdle Thickness: Thick to very thick
Culet Size: None
Polish: Good
Symmetry: Good
Fluorescence: Faint Blue
Dimensions: 5.44-5.47 x 3.49 MM

(Diamond Report is from IGI)

Is this a diamond you have bought or are considering? Where it says diameter ( highlighted) do you mean that is the table measurement? Could you check please?

Also here is a carat weight to mm chart, it is said to be a little optimistic, so use as a guide only. https://www.pricescope.com/community/threads/mm-to-carat-stone-conversion-chart.17578/

 

[Sparkles4Luv]

Yes sorry..I don''t have the certificate with me at this time..but I''m pretty sure that was the table% not the diameter. Sorry for the confusion. I already bought the diamond..it''s the one I currently have in the Coast ring, but I might return it and get a slighlty bigger size. So I want to make sure I get the best one now..even if its not the biggest! Let me know what you think....

 

[Sparkles4Luv]

Hi Ellen~ Thanks for the specs...question...are those specs all percentages or are the angles actual degrees...please clarify if u can.

Here''s kind of a silly question (still learning!!!) but when you give those specs are they good specs in general for any diamond not depending on their size or are they particular to a 3/4-1c diamonds?

Thanks for the help!~

 

[Lorelei]

Date: 3/14/2008 1:44:03 PM
Author: Sparkles4Luv

Hi Ellen~ Thanks for the specs...question...are those specs all percentages or are the angles actual degrees...please clarify if u can.

Here''s kind of a silly question (still learning!!!) but when you give those specs are they good specs in general for any diamond not depending on their size or are they particular to a 3/4-1c diamonds?

Thanks for the help!~

The numbers Ellen gave you can be used for round diamonds regardless of size. Also unless you love the diamond you have, you could find one with a better cut for sure. If you can, stick to AGS0 cut grade diamonds and GIA Excellent, which can make finding a pretty diamond easier. Also the table and depth are in percents, but for crown and pavillion, angles are preferable and said to be most accurate, compared to percentages.

 

[Sparkles4Luv]

what are the pros and cons of buying diamonds online? Obviously price is better but in regards to warranties and making sure it''s eye clean...what have been your experiences?

 

[Sparkles4Luv]

Date: 3/14/2008 2:01:17 PM
Author: Lorelei

The numbers Ellen gave you can be used for round diamonds regardless of size. Also unless you love the diamond you have, you could find one with a better cut for sure. If you can, stick to AGS0 cut grade diamonds and GIA Excellent, which can make finding a pretty diamond easier. Also the table and depth are in percents, but for crown and pavillion, angles are preferable and said to be most accurate, compared to percentages.

Lorelei- what does AGSO cut grade mean? Would you find diamond of this grade at retail stores as well?