Is this round brilliant cut too shallow?

[rr888]

1.44ct H SI1 Round Brilliant
GIA triple excellent
Measurements: 7.37 - 7.41 x 4.42mm
Table: 56%
Depth: 59.9%
Crown: 32 degrees
Pavilion: 41 degrees
HCA score: 0.7 (Excellent light return, excellent fire, excellent scintillation, excellent spread)

It has an excellent spread (very big for a 1.44ct) but I just want to make sure that it is not too shallow. What do you think?

 

[ecf8503]

In general - yes it's shallow. But that's not a bad thing in this case as the angles (including shallower crown angle) seem to all play well together. Can you get an idealscope image?

 

[rr888]

Unfortunately the vendor is not able to obtain an idealscope image -- only a set of "hearts and arrows" images. I'm not sure if these are helpful or informative at all, but here they are:

 

[04diamond<3]

I don't think a 59.9 is too shallow, and I love the numbers! I'd have to see at least a picture, can he give you any pictures? Have you seen it in person?

 

[Gypsy]

I don't think it is too shallow either. I think it's worth buying and taking to an appraiser for an idealscope. Or buying an idealscope yourself As long as they have a good return policy.

 

[yssie]

Well, it wouldn't qualify for any brand of H&A based on those hearts and arrows scope images, but that certainly isn't a dealbreaker unless you particularly want a stone with high optical symmetry.

Post the GIA report number.
Based on the depth girdle isn't terribly thick... but that tells us nothing about girdle minimum, which is the bigger concern. How will you set the stone? Stones w/ shallower crowns/pavs may be at greater risk of chipping.
We also want to know when the report was issued.

 

[rr888]

Well, it wouldn't qualify for any brand of H&A based on those hearts and arrows scope images, but that certainly isn't a dealbreaker unless you particularly want a stone with high optical symmetry.

Post the GIA report number.
Based on the depth girdle isn't terribly thick... but that tells us nothing about girdle minimum, which is the bigger concern. How will you set the stone? Stones w/ shallower crowns/pavs may be at greater risk of chipping.
We also want to know when the report was issued.

Thanks for your input, Yssie. The GIA report number is 1169005167. It was issued on January 24 of this year. We haven't finalized the setting yet, but most likely we would set the stone in a 4-prong halo setting in white gold.

Why do you say that the stone wouldn't classify as H&A? I am fairly new to the diamond business so am not very familiar with how to assess these things, and would love to hear your thoughts.

What do you think of the stone overall?

 

[rr888]

I also notice that this stone is "BIC" according to the HCA tool. From my understanding this means that it has great brilliance but might sacrifice fire. Do you think this is a bad thing? Also, the HCA still gives it an "excellent" for fire, so will the fire really be lacking?

Here is a plain light picture of it from the vendor, if that helps:

 

[WinkHPD]

1.44ct H SI1 Round Brilliant
GIA triple excellent
Measurements: 7.37 - 7.41 x 4.42mm
Table: 56%
Depth: 59.9%
Crown: 32 degrees
Pavilion: 41 degrees
HCA score: 0.7 (Excellent light return, excellent fire, excellent scintillation, excellent spread)

It has an excellent spread (very big for a 1.44ct) but I just want to make sure that it is not too shallow. What do you think?

I have run it through Diamond Calc and I am getting an AGS 2 light performance grade. Personally, with the 41 degreen pavilion angle paired with a 32 degree crown angle I am not surprised. This stone has a flat top with only a 13.7% crown with a 43.5% pavilion depth. I would not expect it to have very good dispersion.

I would expect this diamond to not exhibit great dispersion, but it is a stone I would at least like to see so that I can know if it meets or exceeds my expectations.

Wink

 

[John P]

1.44ct H SI1 Round Brilliant
GIA triple excellent
Measurements: 7.37 - 7.41 x 4.42mm
Table: 56%
Depth: 59.9%
Crown: 32 degrees
Pavilion: 41 degrees
HCA score: 0.7 (Excellent light return, excellent fire, excellent scintillation, excellent spread)

It has an excellent spread (very big for a 1.44ct) but I just want to make sure that it is not too shallow. What do you think?

I am replying by phone, so forgive some generalizations:

Per the HCA this will be a bright diamond. In fact, more in the character-camp of a 60-60 make. This is due to the 32.0 crown height (may actually be 31.8-32.2 due to GIA rounding. From memory, a 56T and 32.0CA results in a crown height of less than 14%, likely 13.3-13.7%. Coupled with the high PA, the LR should be abundant but it will not have the levels of dispersion (colored sparkle) seen in the near-Tolkowsky makes frequently discussed here.

I can confirm once home, but I also believe the best-case AGSL grade for this combination (with appropriate lower halves, normal indexing, etc) to be AGS 1 or 2 in performance; a result of lower predicted dispersive output, as mentioned.

This may cause you no concern as, again, it has great spread and should be quite bright and beautiful. But I thought the make difference (character-camp) was worth a mention.

 

[John P]

Well, I seem to have been writing while Wink was posting.

Same basic observations - thanks for confirming AGSL prediction Wink. However do remember GIA rounds data, which may make for slightly variable results.

 

[WinkHPD]

Well, I seem to have been writing while Wink was posting.

Same basic observations - thanks for confirming AGSL prediction Wink. However do remember GIA rounds data, which may make for slightly variable results.

With or without the rounding, I am impressed that you did in your head what I thought might be the case, but needed to run through Diamond Calc to be sure.

As always my friend, you continue to amaze.

Wink

 

[rr888]

Thanks so much for your replies!

I do notice that the HCA score for this diamond says that fire is "excellent." Does this just mean "excellent" for a BIC, which are generally known to be less strong in fire, or "excellent" overall? Also, according to this table (http://www.diamond-cut.com.au/12_fire.htm) with a table of 56%, pavilion of 41%, and crown of 32%, the HCA fire score should be zero. Doesn't this mean that the fire/dispersion should be really good? Or am I misinterpreting this data?

 

[John P]

HCA has limitations. The grading report is more telling.

The "In Context" information in this post may be interesting:
https://www.pricescope.com/community/threads/ags-0-cut-hca-1-2.198820/#p3619475

 

[rr888]

Ah, yes, that makes perfect sense. Thank you!

This diamond is great for my budget, is definitely eye clean, and gets a great HCA score. However, the AGSL score of 1-2 is obviously less than ideal. Do you think it would be worth it to drop down in size (going to a ~1.3ct) and/or color (I color) in order to get a near-Tolkowsky cut for the same price?

 

[WinkHPD]

Ah, yes, that makes perfect sense. Thank you!

This diamond is great for my budget, is definitely eye clean, and gets a great HCA score. However, the AGSL score of 1-2 is obviously less than ideal. Do you think it would be worth it to drop down in size (going to a ~1.3ct) and/or color (I color) in order to get a near-Tolkowsky cut for the same price?

For me, personally, always.

For you? I do not know. Have you looked at some diamonds of various cutting to know what YOUR eyes like? That is the ONLY proof of the pudding that can answer YOUR question about what is best for YOU!

Wink