Spread % on search by cut

[Bluehammer]

Hello,

I noticed on the search by cut feature from the home page that there is a spread percentage listed on "in house" diamonds for H&A cut. This ranges from approx. +3%/-3%. I assume the higher more positive number means a diamond has more spread (logical right?). I have read some posts that say a diamond can have too much spread (too shallow).

My question is: On the "in house" search should I look for the best diamond I can afford at the 3% level of spread or focus near 0%?

I am new to the search and I am looking for the best possible stone for my money. My understanding is that if I get a good spread then my stone looks all the bigger. I am a value shopper so if a good cut/spread can "add visual weight" then all the better.

My basic (flexiable) parameters are 1.0-1.5 carat, E-G, VS1-VS2, ideal cut. I am trying to keep the stone under $10,000. As always trying for the biggest, brightest, eye clean, and most white stone possible.

Thank you in advance for any input, advice, and knowledge.

 

[JulieN]

Just look for good numbers...if you have a good set of numbers, the spread will take care of itself.

I thnk you could safely go to H and SI1. E and VS1 are usually not considered good buys for the money.

 

[Gypsy]

http://www.whiteflash.com/hearts_arrows/A-Cut-Above-H-A-cut-diamond-714342.htm#

1.5 on cut advisor...

http://www.whiteflash.com/hearts_arrows/A-Cut-Above-H-A-cut-diamond-1177141.htm

1.2 cut advisor

 

[Bluehammer]

Thanks for the info. I agree an "E" stone and "VS1" are a bit of a premium feature (mind clean instead of eye). However, can someone from Pricescope outline the calculation on those spread percentages. Also if they indicate over-spread etc. I am a researcher and it drives me nuts not to know virtually all I can when it comes to purchases. The percentages will not drive my purchase, but I find knowledge to be interesting.

Thanks!

 

[Mara]

if you are searching on cut quality in the PS search, then any of those stones are going to be great performers basically if they are under 2.0 on the HCA...it''s important that you know that first off.

so that said, in terms of spread +/-...typically if a stone has a depth of 60.5 or something similar depending on specs, the spread could be more like a +...because the stone does not have lost diameter in a depth...and a different stone with similar specs but with a depth of 61.7 could be more like a - or maybe a 0 because it could be losing some diameter in the depth OR it could be right at 0.....a stone with a depth of 62.5 will probably have a - because it is going to hide some diameter in the deeper depth.

same with a thin girdle vs a thick girdle. a 62.5 with a thicker girdle is going to be a negative on spread, whereas a 60.5 with a thin girdle is going to be a + most likely.

i don''t know the actual calcs but hopefully this helps a bit (if you didn''t already know this, then if you did nevermind!)...

if that doesn''t make sense or you want to know specifics on what could be making a stone + or - then post some stones and have people critique them. good luck!

 

[Garry H (Cut Nut)]

Date: 7/6/2006 12:14:51 AM
Author: Mara
if you are searching on cut quality in the PS search, then any of those stones are going to be great performers basically if they are under 2.0 on the HCA...it''s important that you know that first off.

so that said, in terms of spread +/-...typically if a stone has a depth of 60.5 or something similar depending on specs, the spread could be more like a +...because the stone does not have lost diameter in a depth...and a different stone with similar specs but with a depth of 61.7 could be more like a - or maybe a 0 because it could be losing some diameter in the depth OR it could be right at 0.....a stone with a depth of 62.5 will probably have a - because it is going to hide some diameter in the deeper depth.

same with a thin girdle vs a thick girdle. a 62.5 with a thicker girdle is going to be a negative on spread, whereas a 60.5 with a thin girdle is going to be a + most likely.

i don''t know the actual calcs but hopefully this helps a bit (if you didn''t already know this, then if you did nevermind!)...

if that doesn''t make sense or you want to know specifics on what could be making a stone + or - then post some stones and have people critique them. good luck!

Girdle definitely makes the most spread difference.
But if the girdle is very thin then you run the risk of chipping

 

[oldminer]

Spread search is a great concept, but limited in use except for round diamonds. We plan to introduce the measure of face-up view surface area to all shapes in the near future on our ImaGem generated reports. This will allow people to compare the visible size appearance of any shape diamond to any other diamond.

A comparison by diameter that is easily done for rounds is far less useful any other shape.
As Paul Slegers has pointed out to me, the reporting of depth percentage can be very misleading, too. The way the new AGS 0 princess cuts are made is so different than other princess cuts, the depth percentage can''t be as useful as a comparision tool as it once was.

 

[Bluehammer]

Here are some spread's from the "in house" search:

These are a couple of the stones that I see. I assume the spread percentage is based upon cut and girdle.

All stones are round ideal, H&A cut.


Carat Depth Table Girdle Dimensions Spread % Crown Pav

1.274 60.6% 55% tn-md-f 7.05x7.07x4.28 2% 34.81° 40.93°
1.264 61.8% 56.73% 1.72 6.95x6.92x4.28 -2% 35° 40.8°
1.26 60.9% 54% tn-md f 7.00x7.03x4.27 1% 35.1° 40.9°
1.248 61% 55% tn-md-f 6.97x6.99x4.26 1% 34.9° 40.8°
1.243 61.6% 57% tn-sl.tk 6.87x6.89x4.24 -3% 34.5° 40.83°
1.23 61.4% 55.3% 1.31 6.94x6.91x4.25 0% 34.5° 40.65°

I am asking about the spread percentage calculation for informational purposes, not to pick the "most pretty" stone based upon numbers only.


Thanks!

 

[Mara]

Carat Depth Table Girdle Dimensions Spread % Crown Pav

1.274 60.6% 55% tn-md-f 7.05x7.07x4.28 2% 34.81° 40.93° : this one has 60.6 depth and thin-med girdle giving it +2 spread
1.264 61.8% 56.73% 1.72 6.95x6.92x4.28 -2% 35° 40.8° : this one has 61.8 depth and a little thicker girdle giving it a -2
1.26 60.9% 54% tn-md f 7.00x7.03x4.27 1% 35.1° 40.9° : 60.9 depth and thin-med girdle give it +1
1.248 61% 55% tn-md-f 6.97x6.99x4.26 1% 34.9° 40.8° : 61 depth and thin-med girdle still give it +1
1.243 61.6% 57% tn-sl.tk 6.87x6.89x4.24 -3% 34.5° 40.83°: 61.6 depth and thin-slightly thick girdle give it a -3
1.23 61.4% 55.3% 1.31 6.94x6.91x4.25 0% 34.5° 40.65° : 61.4 depth and med-ish girdle give it 0

i think of 0 as how a diamond that size ''should'' look diameter wise, where anything larger is a + or smaller is a -.

visually how much of a difference will this -3 or +3 make? you can see it in in the diameter pretty clearly where the -3 where the diameter is 6.88mm average and the +2 where it''s 7.06mm. for almost same size stone in terms of carat weight...you are gaining about .15mm which is nothing to sneeze at in a 1.27c stone.

which is why, me liking as much size as possible for my buck while still getting the best cut diamond possible, like the 60.6ish kind of stones with thin-med girdles because they face up larger than a deeper thicker girdle counterpart. if you are splitting hairs like this and have the option for one or the other, i''d always go for the bigger stone with a little less depth and girdle.

hope that helps...

 

[Bluehammer]

Thank you for the information. Everything helps. I think for now I understand what factors into the spread percentage calculation (depth and girdle mostly), I just do not know the math of what emphasis is placed on girdle vs depth etc.. This may be something only Pricescope can answer.

Thanks again for everyone''s input.