NEED Help for round diamond with low Hca Score 0.7

[heyhoo]

Hi guys, i have been looking for a 0.75 carat F color VVS2 round diamond for my proposal ring. And this is the GIA Report



CARAT : 0.75
DEPTH : 60.9
TABLE : 56
CROWN : 34.5
PAVILLION : 40.6
SYMMETRY : EXELLENT
MEASUREMENTS : 5.87 X 5.91 X 3.59

The vendor said they only have this diamond as the best for my 0.75 carat preferrer. The price is around $3920.
But when i check it at HCA tool , The result is

LIGHT RETURN : EXCELLENT
FIRE : EXCELLENT
SCINTILLATION :EXCELLENT
SPREAD : VERY GOOD
HCA SCORE : 0.7 - EXCELLENT WITH TIC RANGE and the comments bellow




I am seeking for your advice:
Is the diamond cut is really excellent ? or is it too shallow ( because the diamond face up size is bigger than usual ) ?


Much Appreciated
Heyhoo

 

[OoohShiny]

The HCA tool is a rejection tool rather than a selection tool - stones with a score over 2 (maybe 2.5 at a stretch) should be rejected. Stones with a score under 2 are worth a closer look.

Shallower stones face up larger for their carat weight, which is a good thing (presuming you want your diamond to look larger )


Use the search bar at the top of the forum to enter your preferred parameters, and then you can pull up a range of options to look at instead of being stuck with just one stone from the one vendor.

FWIW, though, this stone has strong potential IMHO.

 

[heyhoo]

Thank You @OoohShiny for your reply , how about the pav angle at 40.6 is that too shallow ? because i read the best is 40.8 or near that . My main concern is it true that the diamond can appear dark when viewed close up ? because i can't check the diamond in person and they don't provide me the ideal scope or aset image .

With that angle, will the diamond shine sparklingly ? Can it supposed to be "heart and arrow diamond" with that cutting ? sorry if i ask a silly question because i really don't understand about the diamond

 

[OoohShiny]

The PS-recommended parameters are along these lines:

Table 54-58 %
Depth 60-62.4 %
Pavilion Angle 40.6-40.9 degrees
Crown Angle 34.0-35.0 degrees (maybe up to 35.5 with 40.6 pavilion)

Staying within these parameters will help find diamonds that fall within the 'SuperIdeal' ranges

When the crown angle increases, the pavilion angle decreases - e.g. 40.9 pavilion with 34 crown, but 40.6 pavilion with 35-35.5 crown.

The HCA tool helps show when the crown and pavilion angles complement each other (and that the table and depth also work) so it is a useful tool but you may be limited to how many times you can use it each day.


40.6 pavilion is at the lower end of the acceptable scale, but should be fine. It depends how consistent the cutting of the pavilion facets is - GIA adds each of the 8 facets and then averages them (I think?) which means that rather than all being 40.6 degrees, you might have 40.6, 40.5, 40.7, 40.45, 40.8, 40.5, 40.6, 40.7 (or whatever). When the angle drops below 40.45 degrees (IIRC) that is below the angle of refraction within diamond (again, IIRC!) so you will see leakage.

The ASETscope helps you assess how consistent the cutting is across a stone. If a vendor does not have one, you can always purchase one yourself and then use it either in store or at home


re: a low HCA score looking 'dark' when up-close, that would be too much 'obstruction' (when the viewer's head blocks the light from the diamond). IIRC only certain combinations of Lower Girdle Facet (LGF) lengths, combined with certain sizes of Table, cause that affect, but I cannot remember for sure now... @Karl_K would be the man to confirm, if he is happy to do so!

 

[OoohShiny]

Using the search bar, there are five Whiteflash stones that look to be around the parameters you are seeking:
https://www.pricescope.com/diamonds/YZ02rs

and there are 6 CBI stones on the HPD website:
https://www.hpdiamonds.com/en-us/diamonddetail/HPD10526
https://www.hpdiamonds.com/en-us/diamonddetail/HPD8378
https://www.hpdiamonds.com/en-us/diamonddetail/HPD10719
https://www.hpdiamonds.com/en-us/diamonddetail/HPD9663
https://www.hpdiamonds.com/en-us/diamonddetail/HPD10388
https://www.hpdiamonds.com/en-us/diamonddetail/HPD10354

All of the above are AGS000 so you are guaranteed excellent light return and performance.

(As you will see, there are also some JA stones on that first link, but we are not too keen on JA on the forum recently, seeing as they are making life very difficult for PS users, thanks to removing grading reports and their details from the website!)


If you change to searching for GIA XXX stones within the PS-recommended parameters and an 'Excellent' HCA score (indicating the angles work together), there are 340+ stones currently available - you would need to sift through these more carefully but there seems to be a lot of potential options:
https://www.pricescope.com/diamonds/VE67yp

 

[lovedogs]

Using the search bar, there are five Whiteflash stones that look to be around the parameters you are seeking:
https://www.pricescope.com/diamonds/YZ02rs

and there are 6 CBI stones on the HPD website:
https://www.hpdiamonds.com/en-us/diamonddetail/HPD10526
https://www.hpdiamonds.com/en-us/diamonddetail/HPD8378
https://www.hpdiamonds.com/en-us/diamonddetail/HPD10719
https://www.hpdiamonds.com/en-us/diamonddetail/HPD9663
https://www.hpdiamonds.com/en-us/diamonddetail/HPD10388
https://www.hpdiamonds.com/en-us/diamonddetail/HPD10354

All of the above are AGS000 so you are guaranteed excellent light return and performance.

(As you will see, there are also some JA stones on that first link, but we are not too keen on JA on the forum recently, seeing as they are making life very difficult for PS users, thanks to removing grading reports and their details from the website!)


If you change to searching for GIA XXX stones within the PS-recommended parameters and an 'Excellent' HCA score (indicating the angles work together), there are 340+ stones currently available - you would need to sift through these more carefully but there seems to be a lot of potential options:
https://www.pricescope.com/diamonds/VE67yp

I would go with the CBIs rather than the one you have, because they are guaranteed to be ideal (they are a branded super ideal), and they have outstanding customer service, a great bench, and a $1 upgrade policy if your GF wants to upgrade in the future.

 

[Karl_K]

As long as the pavilion mains dont dip below 40.5(~40.45) it should be fine.
This can be checked by viewing at 1/2 arm distance and the arrows should not be dark.

 

[Dancing Fire]

With that angle, will the diamond shine sparklingly ? Can it supposed to be "heart and arrow diamond" with that cutting ? sorry if i ask a silly question because i really don't understand about the diamond

Possible,but is hard to guess w/o H&A pics.

 

[OoohShiny]

As long as the pavilion mains dont dip below 40.5(~40.45) it should be fine.
This can be checked by viewing at 1/2 arm distance and the arrows should not be dark.

Thank you for your assistance, good sir!