HCA - How It works?

[danny_italia]

Ok everyone, so I've recently been introduced to the Holloway Cut Advisor (HCA) and was wondering if someone could PLEASE tell me how it works.

For example here is the following Diamond:
http://www.jamesallen.com/diamonds/H-SI1-Excellent-Cut-Round-Diamond-1518127.asp

It's a Triple Excellent Diamond yet when you run the numbers through the HCA, it comes back with a terrible Total Visual Performance.

Can someone please tell me how a diamond with an Excellent Cut, Polish and Symmetry can have such terrible performance?

Shape: Round
Carat weight: 1.01
Cut: Excellent
Color: H
Clarity: SI1
Certificate: GIA

Depth: 62.8%
Table: 57.0%
Polish: Excellent
Symmetry: Excellent
Girdle:
Culet:
Fluorescence: None
Measurements: 6.41*6.37*4.02
Crown Angle: 36.0
Crown %: 16.00
Pavilion Angle: 41.0
Pavilion %: 43.50



HCA RESULTS


Selected: 62.8% depth, 57% table, 36° crown angle, 41° pavilion angle
The result is for a symmetrical diamond with a medium girdle and very good polish
HCA scores were adjusted Dec. 15, 2001 and Feb. 6, 2003.


Factor Grade
Light Return Fair
Fire Good
Scintillation Good
Spread
or diameter for weight Very Good

Total Visual Performance 5.5

 

[kenny]

Can someone please tell me how a diamond with an Excellent Cut, Polish and Symmetry can have such terrible performance?

Shocking as it is, GIA's top cut grade includes some no-so-great proportions.
62.8% is kinda deep which saves more rough diamond material and lets the owner make more money.
If that piece of rough was well cut it would have ended up well under 1 carat, instead of 1.01 ct.
Few customers understand good cut but every customer understands weight.
That diamond will sell to someone who doesn't know any better.
Now you know better.

GIA's cut grading system is more industry-friendly than consumer-friendly.
AGS's top cut grade is much more strict, which is why I see AGS as more consumer-friendly.

That other round you posted was also deep.

Do a diamond search on PS...Click on Resoures tab above and select Diamond Search.
Enter your specs and excellent cut.
It will only return rounds with HCA <2.0

 

[danny_italia]

Thanks Kenny for the explaination... im gonna sleep on it and see if I can come up with anymore questions.

For some reason I seem to be having an issue with the pricescope search:

Even though HCA Cut Rank is set to Excellent - "Regular Cut" still turns up all sorts of type. Am i missing something? How do I select only "Excellent Cut"

 

[kenny]

I see what you mean.
It happened to me when I just tried it.

I think PS Diamond Search function is broken.
I'll report it.

 

[kenny]

I'd enter my specs into the search functions of vendors I know to have well cut diamonds, good policies, prices, and reputation, like briangavindiamonds, whiteflash, goodoldgold, craftedbyinfinity, jamesallen.

 

[ChristineRose]

For some reason the search function cannot or will not calculate HCA for most diamonds. To see the HCA rankings for the diamonds it can deal with, click on the the little blue "HCA" at the top of the column. You will rank the diamonds by HCA, with the majority being unranked and at the bottom. What you see in your picture has the unranked diamonds at the top and the handful of ranking diamonds off the bottom of the list of the first 200.

 

[danny_italia]

For some reason the search function cannot or will not calculate HCA for most diamonds. To see the HCA rankings for the diamonds it can deal with, click on the the little blue "HCA" at the top of the column. You will rank the diamonds by HCA, with the majority being unranked and at the bottom. What you see in your picture has the unranked diamonds at the top and the handful of ranking diamonds off the bottom of the list of the first 200.

There are several columns in the list of diamonds 2 of which are "Cut" and "HCA Cut" Is there not a search field for the first cut?

 

[Christina...]

Under the clarity bar you will see three boxes HA, AGS0 GIA3X, click the box for AGS0 and GIA3X and that will limit your search to only excellent and ideal cut stones. I don't know why the HCA information isn't coming up?