Spread: How big of a difference?

[JABacchetta]

Lets say I have a diamond that is .50 and has an "excellent" spread rating on the HCA calculator. How would that compare to a larger diamond that only has a "good" spread rating. Is that half a carat going to look like a .55? .60? .75?

The reason I ask is that I wanted to buy a full carat. However my girlfriends hands are small and she only wants half a carat. I figured I might try to get closer to three quarters. But if I can manage to get a half a carat diamond that looks larger (closer to three quarters) then I would be willing to purchase that and save myself some money.

Any help is much appreciated.

 

[Lorelei]

Date: 6/8/2009 5:20:25 PM
Author:JABacchetta
Lets say I have a diamond that is .50 and has an 'excellent' spread rating on the HCA calculator. How would that compare to a larger diamond that only has a 'good' spread rating. Is that half a carat going to look like a .55? .60? .75?

The reason I ask is that I wanted to buy a full carat. However my girlfriends hands are small and she only wants half a carat. I figured I might try to get closer to three quarters. But if I can manage to get a half a carat diamond that looks larger (closer to three quarters) then I would be willing to purchase that and save myself some money.

Any help is much appreciated.

Having greater spread isn't always a good thing, if you buy a half carat diamond with the spread of a .75 then this could sacrifice cut quality and beauty. Read more here - http://diamonds.pricescope.com/spread.asp

Ideally you want a diamond with a good or appropriate spread for the weight, you can judge the spread by the first two numbers on the diameter in MM. If you find a well cut diamond then the spread should fall into place. Maybe look in between .50 and .75cts, but if your GF expressed she prefers half a carat then I would stick with that. Also shallower depthed diamonds only normally get Ex for spread on the HCA, most top cut diamonds get VG so don't get over reliant on ex for spread on the HCA, VG is fine.

 

[Todd Gray]

Date: 6/8/2009 5:20:25 PM
Author:JABacchetta
Lets say I have a diamond that is .50 and has an 'excellent' spread rating on the HCA calculator. How would that compare to a larger diamond that only has a 'good' spread rating. Is that half a carat going to look like a .55? .60? .75?

More accurately, a properly cut 0.50 carat will face up like a properly cut 0.50 carat (in the range of 5.25 mm in diameter) and a diamond with a lower rating for 'spread' will face up smaller like a 0.45 carat - unless it is cut shallow in which case it might face up like a 0.55 carat, but then it will lack visual performance (in both instances).

I'd recommend searching for a round brilliant ideal cut diamond with a total depth between 59 - 61.8% with a table diameter between 53 - 57% (least important of the factors) and a crown angle between 34.3 - 34.8 degrees offset by a pavilion angle of 40.6 - 40.9 degrees with a girdle thickness between thin to slightly thick and a culet of GIA none or AGS pointed. This combination will increase the possibility of finding a diamond with great visual performance and maintain a balance of carat weight / spread.

Note that you should also take optical symmetry into account (lots of threads here on PS pertaining to optical symmetry and visual performance) and look for dealers who provide you with detailed clarity photographs, proportions analysis, images from the various scopes designed to evaluate optical symmetry (Ideal Scope, ASET, Gems Fantasy).