Experts please me with these HCA results

[in_need_of_help]

Hello All,

Please help with these results. I do not understand why they are not higher.

SARIN ANALYSIS RESULTS:
total depth 61.3%
crown angle 34.2 (33.8-34.6)
crown height 14.4% (14.3-14.7)
pavilion angle 41.0 (40.8-41.2)
pavilion depth 43.5 (42.9-44.0)
culet .02% none
girdle thickness 1.9% (1.5-2.9)
proportion 0

HCA RESULTS:
Factor Grade
Light Return = Excellent
Fire = Very Good
Scintillation = Very Good
Spread = Very Good
Total Visual Performance 1.6 - Excellent - within TIC range

QUESTIONS:
1) This is an AGS ideal cut, how come the fire and scintillation are not higher (excellent)? I think I understand that because the table is 56.6, the spread in only VG; if it were higher, the spread would be higher.

2) The total visual score is excellent scoring 1.6 (TIC), yet 3 out of 4 variables were scored very good (with light return being the exception and scoring excellent). Does the total visual performance add more weight to the light return score than the other variables (fire, scintillation, and spread)?

3) Based on these numbers, is anything alarming to you?

4) Visually, how much different is a HCA total score of 1.6 (light return = X, fire = VG, scintillation = VG, and spread = VG) versus a HCA total score of 1.3 (light return = X, fire = X, scintillation = X, and spread = VG)?

Thanks!


FYI, I was advised not to buy the G colored diamond with the cavity that I was asking about before. It turns out, according to the salesperson, that there is a large feather which does not look good in terms of the its position. The questions above refer to a new diamond that I am considering. Wish me more luck this time.

 

[Mara]

Try changing that 41 pav angle to 40.9...the score changes from 1.6 to 1.3 and now you have 2 EX's...hmmm.




For whatever reason the HCA seems to penalize stones at 41 degrees..I have no idea why...but in my opinion it seems that the stone can't go from EX EX at 40.9 to VG VG or similar at 41...so I would take it with a grain of salt and just use the 1.6 TIC EX as the thing to look at. Many times I change the pav angle from something like 41 to 40.9 and see a signficant change in the HCA score. Don't know if the EYE would actually see any visible change?




Seems this pav angle may be considered a little steep by the HCA to be paired with the lower crown angle. Move the pav angle around a bit and you will see some changes. But move the crown angle and you don't see much change.




Maybe experts can comment....OH RICH....care to post about 15 times on this subject?!?!

 

[in_need_of_help]

Using a Pav angle of 40.9 changes only fire from VG to Ex, everything else remains the same

. I feel like I'm manipulating the data by not using the true average scores.

 

[Hest88]

To put it into RL perspective: the odds of the eye seeing a difference between an EX and a VG score are pretty slim. If you're under a deadline and the price is right, I wouldn't get too caught up over these numbers. Whatever you decide, though, good luck!

 

[in_need_of_help]

What is RL?

What makes it more complicated is that I still am within my budget and not up against an urgent deadline. Therefore, I always wonder if this is the ONE or if I should continue my search.

 

[Mara]

I say keep looking--if you are within budget still and within deadline. There are always going to be other diamonds out there--so until you are SURE that this is the one, don't buy..or else it will drive you nuts later that you didn't use your time and $ to the fullest advantage. My perspective.

 

[in_need_of_help]

Would any one be willing to plug in these numbers to DiamCalc or any other analyses to help me decide.

Thanks!

 

[Mara]

Ohhh Richhhh...

 

[pqcollectibles]

RL = Real Life

Would your eye see a visual difference in daily life between Ex and VG?? Dunno. I think you'd have to see it to know for sure.

But maybe Rich will answer this one for us. Ohhh Riiccchhh!!

 

[in_need_of_help]

Anyone else?

 

[Colored Gemstone Nut]

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On 11/10/2003 10:03:18 PM in_need_of_help wrote:





Anyone else?
----------------

In Need Of Help,

Respectfully Garry has worked very hard in creating a system to weed out poor performing stones.

Garry's system is not the end all say all....

I would use an ideal-scope to check leakage of the stone you are looking at. It is one of the cheapest and most affective tools in evaluating light leakage which is available to consumers..

I think the stone you listed warrants consideration and furthermore looking at it in person or getting an independent evaluation done which you might be able to make the sale contingent upon the results...

Crown & Pav. angle are very dependent on one another and can have a direct result on light performance...

What is important to you in a diamond you are looking at...(Leave the numbers out of the equation for now)

 

[Caratz]

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On 11/10/2003 10:03:18 PM in_need_of_help wrote:

Anyone else?----------------

I think Garry's own disclaimer is key: "A score below 2 (Excellent) means you have eliminated known poor performers (more than 95% of all diamonds). Your own personal preference may be for a diamond with an HCA score of 1.5 more rather than one with a lower score of say 0.5."

 

[Garry H (Cut Nut)]

A diamond with a tiny bit of leakage from the slightly deep pavilion (with that crown angle) like this one will perform very well if it is worn on a ring in an open setting so light can get in the pavilion because some of it will come out as fire

AGS choose a system based on human convenience - not one based on good science.

Cheers
Garry