Find your diamond
Find your jewelry
shape
carat
color
clarity

Important changes to HCA Cut Adviser

Status
Not open for further replies. Please create a new topic or request for this thread to be opened.

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
14,901
More than a year ago we decided that HCA was too strict, and so we reduced the penalty severity to 2/3rds of the previous rating.

We feel that we went a little too far and after some more research we decided to adjust the penalty to a midway point.
As stated in the fine print with every report ¡§This system is being continually fine-tuned and results may change without notice.¡¨

There have also been other changes made too the light return scores:

1. The penalty for table sizes has been tightened to 55% to 56%. Above and below this range a gradual penalty is added. The range covers 75% to 40% tables.
2. Some shallower proportion combinations have been penalised more heavily. This is a result of debates with Sergey Sivovolenko and Yuri Shelementiev from OctoNus and Moscow State Uni, and also Brian Gavin from A Cut Above. These debates led to surveys which showed that preferences for say 40.0„a pavilions combined with 33„a crown angled diamonds are variable ¡V some people love the star that never goes away, and others hate the effect. Overall I decided it is better to guide people to ¡§usual and normally accepted cuts¡¨ (to quote Dave Atlas).

I would like to thank all the other people who have contributed, including antagonists (Hi Roc
http://www.consumersgemlab.com/the_holloway_cut_adviser.htm ) and objective observers like Jasper Paulsen http://www.folds.net/diamond_design/index.html#ed_note_02

We hope that these changes have not inconvenienced anyone overly.
You can read more about the theory and mechanisms behind HCA at www.diamond-cut.com.au - although some of the information there will not reflect this recent change.
 

RockDoc

Ideal_Rock
Joined
Aug 15, 2000
Messages
2,509
Garry

If my antagonism makes the product better and reliable, then I accomplished some of what I think is to the advantage of consumers.

40-75% TABLES PENALTIES?

I think until an industry accepted standard is reached where everyone agrees, I am not sure that the analysis is really helpful.

Now if you can get the industry to go along with your "formula" instead of AGS or others, and its accepted - then we have a different story.

Rockdoc
 

AmPm

Rough_Rock
Joined
Feb 6, 2003
Messages
47
We all do our bit Roc, and we hope some people appreciate what we do


Re large table ranges - do a search and see how many very large table >65% diamonds there are. I think this is quite relevant.

But what about the shallow stone critcism you have made in the past?

BTW we have a few ideas to help consumers eliminate poor symmetry stones from searches to make the whole search process much quicker and easier
 

dymonite

Rough_Rock
Joined
Oct 7, 2002
Messages
49
----------------
On 2/6/2003 6:37:54 PM Cut Nut wrote:

You can read more about the theory and mechanisms behind HCA at www.diamond-cut.com.au - although some of the information there will not reflect this recent change.


----------------

Garry,

Wil we be seeing an update of the revised HCA methodology in the near future? I think it will be important for people to see how you have justified these changes.



D
 
Status
Not open for further replies. Please create a new topic or request for this thread to be opened.
Be a part of the community It's free, join today!

Need Something Special?

Get a quote from multiple trusted and vetted jewelers.

Holloway Cut Advisor



Diamond Eye Candy

Click to view full-size image.
Top