Trying to understand the HCA just a little better....

[valeria101]

Great!

It was good to see the discussion unfold.

Since your post invites comments, I would have three:

The text is short, but has become very dense. It makes more of an invitation to read through tutorials than a stand-alone piece. Some issues it refers to (dirty pavilions, viewing distance) must be in the Ideal Scope newsletters not the reference given and some...

The inference chain between ''better vision'' and ''dark diamonds'' reminds me of how old professors and young colleagues read my microscopic hand writing - it is the old ones with worse vision that put their nose close to the paper. The next sentence mentions ''normal social viewing distance'' (could be ''socially acceptable'') and that makes a better argument, IMO.

Regarding the list of what the HCA does not consider (symmetry, polish, minors) - it begs the question ''why not''. There is no mention of optical symmetry, and anyone who is not familiar with that fine line would probably wonder why not just let folk write in the finish grades from the lab reports? If there is a two-word way to explain why these four factors and not others enter the HCA score, I would put it in there.


Anyway... perhaps these do not matter all that much. There''s always the forum to answer Qs

 

[Garry H (Cut Nut)]

Thanks Ana

how do we make it less dense?
Added the social bit

Date: 11/14/2005 2:57:43 AM
Author: Garry H (Cut Nut)Holloway Cut Adviser

The Holloway Cut Adviser (patent pending) estimates a round diamonds appeal, based on its potential Light Return, Fire, Scintillation and Spread.

Most people prefer stones that rate 1-2 on a scale where: 0-2 Excellent, 2-4 Very Good, 4-6 Good, 6-8 Fair, and 8-10 Poor. Zero is almost impossible since many of the factors conflict.

You must enter Total Depth %, Table % and Crown° and Pavilion° angles which you can get from AGS and 2006 GIA and IGI reports. Some reports list rounded Crown % and Pavilion %’s which are less accurate, but if a stone scores under 2.0, ask the vendor for a Helium, Sarin or Ogi report with angles.

Because HCA gets no symmetry, polish and minor facets info, please only use it as a rejection tool for likely bad performing diamonds & to narrow down your final selection. Ideal-Scope images and independent appraisers can help after that.

The tutorial explains more about Cut and diamond beauty. More about HCA at www.diamond-cut.com.au.

Now this is the warning that appears after result:
Only use HCA to reject diamonds & narrow down your selection.

GIA’s new system is similar to HCA, but adds symmetry, polish and minor facet info. But steeper crown and deeper pavilion combination GIA ‘Excellent’s’ may not look as good when they are dirty.

Consider using an expert appraiser for your final selection, or compare the stone to other well cut diamonds and / or view it through an ideal-scope. A score below 2 (red on the chart) means you have by passed diamonds with too much leakage or darkness, overly thin or thick girdles & fish-eyes. But there are other negatives that HCA can’t predict. Many people prefer diamonds with a score between 1.0 and 2.0, to shallower stones which often score less than 1.0 down to zero.

Shallow stones (lower left on the chart) look darker than stones with proportions on the upper edges of the red zone. The better your close up vision and the closer your head is to the diamond, the more light sources you will obstruct. Looked at this why shallow diamonds appear darker than diamonds with HCA''s of 1 to 2. But shallow diamonds have a bigger spread, and are great for pendants and earrings, where socially acceptable viewing distances apply.

Stones near the center of the red region (the lowest scores) are least affected by symmetry variations. Alternatively hearts and arrows diamonds, which have excellent optical symmetry, but often HCA scores around 2, may out-perform diamonds with lesser symmetry and lower HCA scores.

Deeper stones in the upper green and blue zones have more leakage and often appear dark just inside the table and the outer girdle edges; they are best set in open backed rings so light can get in the bottom or pavilion. But small ‘vee’ shaped leakage zones near the outer edges of a diamond, as seen with an Ideal-Scope, can add to a diamonds contrast and brilliance.

The ‘X’ on the chart marks the pavilion° / crown° position. The white outline shows the AGS ideal candidates range. HCA is fine-tuned from time to time - results may change without notice.

Garry Holloway FGAA DDT

 

[valeria101]

Date: 11/14/2005 5:00:23 AM
Author: Garry H (Cut Nut)
Thanks Ana

how do we make it less dense?
Added the social bit

Date: 11/14/2005 2:57:43 AM
Author: Garry H (Cut Nut)Holloway Cut Adviser



Now this is the warning that appears after result:

...

Shallow stones (lower left on the chart) look darker than stones with proportions on the upper edges of the red zone. The better your close up vision and the closer your head is to the diamond, the more light sources you will obstruct. Looked at this why shallow diamonds appear darker than diamonds with HCA''s of 1 to 2. But shallow diamonds have a bigger spread, and are great for pendants and earrings, where socially acceptable viewing distances apply.

Is it meant to be: "This is why shallow..." ?

With the previous comment I was mostly trying to put myself in the shoes of someone who only reads that page about diamonds and looks for an easy way to put a score on blind choices or tell apart cut grades on different lab reports (eg. IGI and GIA or what not). From such perspective, it may be ok to match the words ''crown'' and ''pavilion'' between the Lab report and the HCA input screen, but this is about it. Thankfully, few would try to associate that information with the following details about visual effects - what diamonds look like from close by and further away, set in open and closed settings, clean or not quite (there might be others in the text, just stopped the count).

So... I would think the relation between numbers and looks is not trivia, but may be just beyond usual worries. If this is not the case, it may take some explaining to do. GIA''s page on cut does it and I suppose their rhetoric will catch.

What seems more obvious is that with HCA and GIA & AGS or Sarin paper infront it is obvious some variables are left out and there is no explanation why. One doesn''t need to know anything about diamonds to get this. And the knee-jerk interpretation is that HCA scores are some very poor sister or very low common denominator of the grading available on lab reports.


Anyway, I have to admit I could keep at it for eons. If the observations make sense, I could work them into the text or... whatever is useful.

 

[Garry H (Cut Nut)]

Date: 11/14/2005 5:00:23 AM
Author: Garry H (Cut Nut)
Thanks Ana

how do we make it less dense?
Added the social bit

Date: 11/14/2005 2:57:43 AM
Author: Garry H (Cut Nut)Holloway Cut Adviser

The Holloway Cut Adviser (patent pending) estimates a round diamonds appeal, based on its potential Light Return, Fire, Scintillation and Spread.

Most people prefer stones that rate 1-2 on a scale where: 0-2 Excellent, 2-4 Very Good, 4-6 Good, 6-8 Fair, and 8-10 Poor. Zero is almost impossible since many of the factors conflict.

You must enter Total Depth %, Table % and Crown° and Pavilion° angles which you can get from AGS and 2006 GIA and IGI reports. Some reports list rounded Crown % and Pavilion %’s which are less accurate, but if a stone scores under 2.0, ask the vendor for a Helium, Sarin or Ogi report with angles.


Because HCA gets no symmetry, polish and minor facets info, please only use it as a rejection tool for likely bad performing diamonds & to narrow down your final selection. Ideal-Scope images and independent appraisers can help after that.

The tutorial explains more about Cut and diamond beauty. More about HCA at www.diamond-cut.com.au.

Now this is the warning that appears after result:

Only use HCA to reject diamonds & narrow down your selection.

GIA’s new system is similar to HCA, but adds symmetry, polish and minor facet info. But steeper crown and deeper pavilion combination GIA ‘Excellent’s’ may not look as good when they are dirty.

Consider using an expert appraiser for your final selection, or compare the stone to other well cut diamonds and / or view it through an ideal-scope. A score below 2 (red on the chart) means you have by passed diamonds with too much leakage or darkness, overly thin or thick girdles & fish-eyes. But there are other negatives that HCA can’t predict. Many people prefer diamonds with a score between 1.0 and 2.0, to shallower stones which often score less than 1.0 down to zero.

Shallow stones (lower left on the chart) look darker than stones with proportions on the upper edges of the red zone. The better your close up vision and the closer your head is to the diamond, the more light sources you will obstruct. Looked at from very close, shallow diamonds appear darker than diamonds with HCA''s of 1 to 2. But shallow diamonds have a bigger spread, and are great for pendants and earrings, where socially acceptable viewing distances apply.

Stones near the center of the red region (the lowest scores) are least affected by symmetry variations. Alternatively hearts and arrows diamonds, which have excellent optical symmetry, but often HCA scores around 2, may out-perform diamonds with lesser symmetry and lower HCA scores.

Deeper stones in the upper green and blue zones have more leakage and often appear dark just inside the table and the outer girdle edges; they are best set in open backed rings so light can get in the bottom or pavilion. But small ‘vee’ shaped leakage zones near the outer edges of a diamond, as seen with an Ideal-Scope, can add to a diamonds contrast and brilliance.

The ‘X’ on the chart marks the pavilion° / crown° position. The white outline shows the AGS ideal candidates range. HCA is fine-tuned from time to time - results may change without notice.

Garry Holloway FGAA DDT

thx Ana.
I am too tired to understand the rest of your words

 

[valeria101]

Date: 11/14/2005 5:35:55 AM
Author: Garry H (Cut Nut)

thx Ana.
I am too tired to understand the rest of your words

Thanks... always this time zone

It''s back to work for me.

 

[strmrdr]

Date: 11/14/2005 12:54:34 AM
Author: Rhino

Date: 11/13/2005 11:22:03 PM

Author: strmrdr

going to have to disagree with you a bit rhino:


''indicates that the majority of facets are functioning as reflectors as opposed to leakers.''


The hca does not tell you that, an IS image does.

for example a stone with an average of 40.9 but a range of 40.6 to 41.5


The hca tells you mainly that the average crown angle works well with the average pavilion angle.


Paul would say when cutting to the edge like he does, that what is in the average can be more important than the average.

I hear your point. Think about it though ... Garry devised the HCA using what? The mother to the IS.


We know for a fact it does indeed eliminate what? Stones with excessive leakage eh? I know there are stones out there with wild variances but at least with a good average pavilion angle at least a good portion of them will be functioning as reflectors. Bear in mind its not perfect just as any technology isn''t perfect. I don''t think that''s the goal here. But at least with good averages it puts a person in the ball park of having a stone wherein the predominant majority of facets are functioning as reflectors. That is a good ball park to be in for starters I would say. If the HCA was going to take into account variances then a whole lot more information would be needed and the HCA is not designed to do this (neither is GIA''s FacerWare for that matter). For the simplistic purposes the HCA was designed for, while I like your idea of *knowing the variances*, I''d leave that for 2nd/3rd round considerations for those who would want to know or care.


What do you think? Does that sound reasonable?

I see and saw where you were coming from and why,
The goal is to simplify as much as possible while increasing the accuracy of the descriptions of what hca does.
Which is why I had to disagree.
Going your proposed route would require a much longer explaination and without talking about averages be less accurate.

 

[belle]

garry,
hca is a simple and straightforward tool in terms of use. the more disclaimers and distinctions you add, the more you take away from it''s intended purpose. let''s not get bogged down, there are only a few things that need to be addressed:

1. what it is
2. how it is used



1. the hca is a tool used to identify known poor performing diamonds based on relative proportion combinations. scores are issued on a numerical scale according to predicted compatibility of these combinations. hca does not yet factor in symmetry and minor facets which can influence the overall performance and therefore should not be used as an independant tool for final selection among otherwise excellent diamonds.

2. based on the proportions entered diamonds are scored as follows: 0-2 Excellent, 2-4 Very Good, 4-6 Good, 6-8 Fair, and 8-10 Poor. all scores under 2 are considered excellent but because the combinations become extreme as they get closer to zero, the lowest scores should not be considered the best. most people will prefer stones with proportion combinations that rate around the 1-2 range. Zero is almost impossible since many of the factors conflict.


trying to describe each situation (old people rings, young people rings, pendant vs. ring) only gets confusing for the user.
K.I.S.S.

 

[JohnQuixote]

Date: 11/14/2005 5:35:55 AM
Author: Garry H (Cut Nut)

Date: 11/14/2005 5:00:23 AM
Author: Garry H (Cut Nut)
Thanks Ana

how do we make it less dense?
Added the social bit

Date: 11/14/2005 2:57:43 AM
Author: Garry H (Cut Nut)Holloway Cut Adviser

The Holloway Cut Adviser (patent pending) estimates a round diamonds appeal, based on its potential Light Return, Fire, Scintillation and Spread.

Most people prefer stones that rate 1-2 on a scale where: 0-2 Excellent, 2-4 Very Good, 4-6 Good, 6-8 Fair, and 8-10 Poor. Zero is almost impossible since many of the factors conflict.

You must enter Total Depth %, Table % and Crown° and Pavilion° angles which you can get from AGS and 2006 GIA and IGI reports. Some reports list rounded Crown % and Pavilion %’s which are less accurate, but if a stone scores under 2.0, ask the vendor for a Helium, Sarin or Ogi report with angles.


Because HCA gets no symmetry, polish and minor facets info, please only use it as a rejection tool for likely bad performing diamonds & to narrow down your final selection. Ideal-Scope images and independent appraisers can help after that.

The tutorial explains more about Cut and diamond beauty. More about HCA at www.diamond-cut.com.au.

Now this is the warning that appears after result:

Only use HCA to reject diamonds & narrow down your selection.

GIA’s new system is similar to HCA, but adds symmetry, polish and minor facet info. But steeper crown and deeper pavilion combination GIA ‘Excellent’s’ may not look as good when they are dirty.

Consider using an expert appraiser for your final selection, or compare the stone to other well cut diamonds and / or view it through an ideal-scope. A score below 2 (red on the chart) means you have by passed diamonds with too much leakage or darkness, overly thin or thick girdles & fish-eyes. But there are other negatives that HCA can’t predict. Many people prefer diamonds with a score between 1.0 and 2.0, to shallower stones which often score less than 1.0 down to zero.

Shallow stones (lower left on the chart) look darker than stones with proportions on the upper edges of the red zone. The better your close up vision and the closer your head is to the diamond, the more light sources you will obstruct. Looked at from very close, shallow diamonds appear darker than diamonds with HCA''s of 1 to 2. But shallow diamonds have a bigger spread, and are great for pendants and earrings, where socially acceptable viewing distances apply.

Stones near the center of the red region (the lowest scores) are least affected by symmetry variations. Alternatively hearts and arrows diamonds, which have excellent optical symmetry, but often HCA scores around 2, may out-perform diamonds with lesser symmetry and lower HCA scores.

Deeper stones in the upper green and blue zones have more leakage and often appear dark just inside the table and the outer girdle edges; they are best set in open backed rings so light can get in the bottom or pavilion. But small ‘vee’ shaped leakage zones near the outer edges of a diamond, as seen with an Ideal-Scope, can add to a diamonds contrast and brilliance.

The ‘X’ on the chart marks the pavilion° / crown° position. The white outline shows the AGS ideal candidates range. HCA is fine-tuned from time to time - results may change without notice.

Garry Holloway FGAA DDT

thx Ana.
I am too tired to understand the rest of your words

Hi all. Been on vacation. A lot to digest. The content prior to the result has good information.


Coming in, not having seen this since page 3...are we reinventing the wheel too much?

(1) Is there any way to trim down the wording after the result? It''s quite lengthy.

(2) Though the intent is good, I worry about wording that seems to condemn the look of shallow diamonds. I worked with a client not too long ago that preferred the look of a center stone she already owned scoring p]

 

[aljdewey]

Date: 11/14/2005 12:30:24 PM
Author: JohnQuixote

(2) Though the intent is good, I worry about wording that seems to condemn the look of shallow diamonds. I worked with a client not too long ago that preferred the look of a center stone she already owned scoring < 1.0 (it has a 40.2 PA) to configurations she''s seen in the 1.X range. This is not as common as the other way around in my experience, but there are people out there who prefer it. Food for thought.

Well, I hope someone has a plan to call that client to advise her that her preference is wrong and that she picked a dud. I''m sure she''ll be greatly swayed to learn this.

 

[Garry H (Cut Nut)]

Date: 11/14/2005 1:24:38 PM
Author: aljdewey

Date: 11/14/2005 12:30:24 PM
Author: JohnQuixote

(2) Though the intent is good, I worry about wording that seems to condemn the look of shallow diamonds. I worked with a client not too long ago that preferred the look of a center stone she already owned scoring < 1.0 (it has a 40.2 PA) to configurations she''s seen in the 1.X range. This is not as common as the other way around in my experience, but there are people out there who prefer it. Food for thought.

Well, I hope someone has a plan to call that client to advise her that her preference is wrong and that she picked a dud. I''m sure she''ll be greatly swayed to learn this.

Burn her - burn the evil little witch

 

[Garry H (Cut Nut)]

Thanks Belle,

What about your version at the start, and more detailed under the result?

 

[Garry H (Cut Nut)]

Date: 11/14/2005 12:30:24 PM
Author: JohnQuixote


Hi all. Been on vacation. A lot to digest. The content prior to the result has good information.


Coming in, not having seen this since page 3...are we reinventing the wheel too much?

(1) Is there any way to trim down the wording after the result? It''s quite lengthy. You are the master word smith John, care to have a crack at it?
But it is a bit of a case of the man and his donkey.

(2) Though the intent is good, I worry about wording that seems to condemn the look of shallow diamonds. I worked with a client not too long ago that preferred the look of a center stone she already owned scoring < 1.0 (it has a 40.2 PA) to configurations she''s seen in the 1.X range. This is not as common as the other way around in my experience, but there are people out there who prefer it. Food for thought.

 

[valeria101]

Garry, is this thread intended to collect every critique of the HCA from here to eternity, deterring detractors by sheer research burden?

It is quite funny how the ''just a little better'' took 130 posts by now !

 

[aljdewey]

Date: 11/14/2005 3:16:06 PM
Author: valeria101



Garry, is this thread intended to collect every critique of the HCA from here to eternity, deterring detractors by sheer research burden?

It is quite funny how the ''just a little better'' took 130 posts by now !

Yep - that''s because people cannot be trusted to read a few simple, straightforward lines about the HCA and digest it. No, it''s better to disqualify the ever loving daylights out of every single syllable so it''s all "official" looking. Maybe we''ll even confuse them to the point where they won''t feel comfortable shopping for a diamond at all....won''t that be special!

Next, we''re going to have to define the word "diamond" for those we think might not be bright enough to figure it out for themselves......because after all, what if they think the HCA is meant to determine the lifespan of their next auto purchase? HORRORS. We must save them from themselves! Quick.....someone please write 3 MORE paragraphs to add to the huge disclaimer so people understand the HCA should not be used to calibrate one''s carburetor! Because if we don''t say it, no one will be able to figure it out on their own.

What a ridiculous waste of collective resources.

This is what the HCA presently says: "The Holloway Cut Adviser (patent pending) estimates a round diamonds appeal based on its potential Light Return, Fire, Scintillation and Spread.

Most people prefer stones that rate 1-2 on a scale where: 0-2 Excellent, 2-4 Very Good, 4-6 Good, 6-8 Fair, and 8-10 Poor. Zero is almost impossible since many of the factors conflict.

You need Total Depth %, Table % and Crown° and Pavilion° angles from AGS and 2006 GIA and IGI reports. Some reports list less accurate rounded Crown % and Pavilion %’s; run the stone and if it scores under 2.0, ask the vendor to get you a Helium, Sarin or Ogi report with angles.

HCA gets no info on symmetry, polish and minor facets; use it only to reject likely bad performing diamonds to narrow down your final selection. Ideal-Scope images and independent appraisers can help after that."

How hard to do we have to make it, folks?

 

[Rhino]

Date: 11/14/2005 12:01:20 PM
Author: belle

garry,
hca is a simple and straightforward tool in terms of use. the more disclaimers and distinctions you add, the more you take away from it''s intended purpose. let''s not get bogged down, there are only a few things that need to be addressed:

1. what it is
2. how it is used



1. the hca is a tool used to identify known poor performing diamonds based on relative proportion combinations. scores are issued on a numerical scale according to predicted compatibility of these combinations. hca does not yet factor in symmetry and minor facets which can influence the overall performance and therefore should not be used as an independant tool for final selection among otherwise excellent diamonds.

2. based on the proportions entered diamonds are scored as follows: 0-2 Excellent, 2-4 Very Good, 4-6 Good, 6-8 Fair, and 8-10 Poor. all scores under 2 are considered excellent but because the combinations become extreme as they get closer to zero, the lowest scores should not be considered the best. most people will prefer stones with proportion combinations that rate around the 1-2 range. Zero is almost impossible since many of the factors conflict.


trying to describe each situation (old people rings, young people rings, pendant vs. ring) only gets confusing for the user.
K.I.S.S.

LOL ... I like this best! It is simple (always loved the KISS method) and straightforward and lets consumers know that the lowest scores aren''t necessarily the best which addresses the point that Mark (the recent newbie) brought up.

Perhaps a line about the stones between 1-2 but then again as Ana has pointed out in a prior post, you can have the same stone and when you punch in the AGS numbers get a .8, then using the Sarin on that same stone get a 1.3. This contributes to unneccary confusion to the user. Belle''s comment is more general and addresses the situation. The user is counseled to seek professional advice anyhow so if they are paying attention to what they are reading they will indeed do that and we get questions all the time about it so apparently people are paying attention.

I apologize for bringing this up again but it is easy for a person ... any person, to also confuse HCA scores under 2 with "ideal cuts" because stones under 2 do include many ideal cuts. It is an assumption I''ve noted more than once on this forum and is an understandable mistake. I know people do not do this on purpose here as they are only seeking to help others which is excellent and commendable. I know the term ideal is not mentioned in the nomenclature but do you think a line should be included to avoid confusion for new people who are using it? Perhaps a sentence stating ...

While many GIA/AGS ideals do in fact score under a 2 on the HCA the user should not presume that all scores of under 2 are in fact ideal cut diamonds. In fact the higher the score the less the chances are of the stone being such.

Or something to that effect. I''m interested in your thoughts belle. My experience with actual diamonds and the best HCA scores have proved this to me time and time again.

Read your post John. Hope you had a good vacation. Regarding the wording that seems to condemn shallow stones, you and I know there are markets for such stones and may indeed be the personal preferences of many folks but to throw them into the lump with ideal cuts and hold them on the same level (even making them appear as being better with the better HCA score) I don''t think is fair to those stones which do in fact have a more appealing appearance in more lighting environments (the actual ideal cuts). This is where the confusion can come into play for John Q Public.

As I find the time to read here I see many times consumers who will punch in the numbers, post the scores and naturally lean towards the lower scoring stone (even the folks here encouraging it). It is natural. I see the same exact thing with other technologies as well which I find myself correcting every so often. Folks naturally assume that the highest BrillianceScope results will be the most appealing to their eyes. As it is with the HCA ... this is not always the case. I''ve seen triple VH stones that were dogs in some of the most common lighting conditions. I think there should be some sentence to indicate this to the newbies who use it but in the general sense of the nomenclature I think belle has hit the nail on the head. If they want to learn more they can go to the tutorial or perhaps a short read of a paragraph or 2 after they get the score. That''s where all the business about earrings and pendants should be included. All of this has prompted me to write an article on the subject.

Till tomorrow.

Kind regards,

 

[Rhino]

Date: 11/14/2005 1:59:41 PM
Author: Garry H (Cut Nut)

Date: 11/14/2005 1:24:38 PM
Author: aljdewey

Date: 11/14/2005 12:30:24 PM
Author: JohnQuixote

(2) Though the intent is good, I worry about wording that seems to condemn the look of shallow diamonds. I worked with a client not too long ago that preferred the look of a center stone she already owned scoring < 1.0 (it has a 40.2 PA) to configurations she''s seen in the 1.X range. This is not as common as the other way around in my experience, but there are people out there who prefer it. Food for thought.

Well, I hope someone has a plan to call that client to advise her that her preference is wrong and that she picked a dud. I''m sure she''ll be greatly swayed to learn this.

Burn her - burn the evil little witch

Don''t have time to comment further at this moment but ROFLMAO! You forgot the tar and feathering part mate.

 

[Regular Guy]

Progress made….

Ok, in this recent fresh breathe of life into this thread, a new turn has been made to look at how the HCA tool is presented to users. This is probably good, as it also throws new light on the use of the tool, altogether. There are implications that have come forward from these discussions, the third of which may present a need for a new thread, designed to look again more closely at what this original thread was designed to address…but for now, I’m only addressing the first 2 ideas here. If the need is present, maybe someone more skillful than me will try to execute the third idea, concerning HCA basics, the difference between 0 – 1 and 1 – 2, and such; we’ll see. For now, this is what comes forward, it seems to me:

#1 – When to use the HCA.

- If diamond has a recent AGS0 cert, nevermind, get a nap.
- If diamond has an older AGS0 cert, screen against HCA, include in review if conforms to 0-2, reject otherwise
- If diamond has any other cert today (GIA doesn’t yet provide the necessary data, other certs provide some of the data), get the data to populate HCA, include in review if conforms to 0 – 2, reject otherwise
- If diamond has a GIA cert after first of the year, reject if not excellent. If excellent, also screen against HCA, include in review if conforms to 0 – 2, reject otherwise

#2 – How to Use the HCA

Garry, you might thunk on this one, depending on your intention of actual intended use (i.e., step b causes me and perhaps others to scrunch their eyes and furrow their brow as many of us really don’t frequently think about where the cross hairs of crown & pavilion angles meet typically, so you may want to consider how essential you want it to be for a typical screening process).

Two part test:

a) Plug in the numbers, determine if the diamond conforms to 0 – 2 test
b) See where you option lands on the chart, and determine if the diamond you are considering
- fits who you are (by age)
- fits your intended use (as a ring, pendent, etc.)

#3 – Factors associated with the HCA.

Getting at these was perhaps the original intent of this thread. It’s fine that it’s wandered. There may be no need to come back here. The idea is that a number of factors have been associated with the HCA, that are probably neither randomly associated with it, nor “one to one” in nature (like, despite it''s essentially linear makeup where low is good and high is bad, head obstruction issues and possibly lighting environment issues, and the like seem to intervene). Some of us are curious. And, if we want to use this tool to help us make a purchase, we may be more than curious. Also, for those who would rather not see a whole spectrum of options scoring 0 – 1 go down the crapper, this may present a renewed focus. Hopefully, someone more able than me will try to address those questions in a thoughtful enough way that some good critical intelligence will be brought to them. But, until such time, I’m guessing that some people will tend to ditch these options (0 – 1) when they may not need to. It’s meanwhile possible that directions in 2b above will satisfy these concerns, and all options scoring 0 – 2 can be considered equally, taking the suggested measures in hand.

Just some thoughts…

 

[belle]

the new format is nice garry.
i''ll admit though, i was surprised to learn that the "better your close up vision, the more light sources your head can obstruct"
i guess the effects of eating carrots is more powerful than i thought!

 

[Regular Guy]

I too like the continued clean look of page 2 (after data is input, and the result is displayed). The new page 3, where additional info is presented, seems to have the right sense of additional info to add perspective.

 

[JohnQuixote]

Good work Garry. I like the 3 page format, with the most in-depth and taste-oriented information on the 3rd. That is also a nice place to be able to document the history of the HCA and such information. Huzzah.

 

[Mara]

Date: 11/15/2005 11:47:09 AM
Author: Regular Guy

Progress made….

Ok, in this recent fresh breathe of life into this thread, a new turn has been made to look at how the HCA tool is presented to users. This is probably good, as it also throws new light on the use of the tool, altogether. There are implications that have come forward from these discussions, the third of which may present a need for a new thread, designed to look again more closely at what this original thread was designed to address…but for now, I’m only addressing the first 2 ideas here. If the need is present, maybe someone more skillful than me will try to execute the third idea, concerning HCA basics, the difference between 0 – 1 and 1 – 2, and such; we’ll see. For now, this is what comes forward, it seems to me:

#1 – When to use the HCA.

- If diamond has a recent AGS0 cert, nevermind, get a nap.
- If diamond has an older AGS0 cert, screen against HCA, include in review if conforms to 0-2, reject otherwise
- If diamond has any other cert today (GIA doesn’t yet provide the necessary data, other certs provide some of the data), get the data to populate HCA, include in review if conforms to 0 – 2, reject otherwise
- If diamond has a GIA cert after first of the year, reject if not excellent. If excellent, also screen against HCA, include in review if conforms to 0 – 2, reject otherwise

#2 – How to Use the HCA

Garry, you might thunk on this one, depending on your intention of actual intended use (i.e., step b causes me and perhaps others to scrunch their eyes and furrow their brow as many of us really don’t frequently think about where the cross hairs of crown & pavilion angles meet typically, so you may want to consider how essential you want it to be for a typical screening process).

Two part test:

a) Plug in the numbers, determine if the diamond conforms to 0 – 2 test
b) See where you option lands on the chart, and determine if the diamond you are considering
- fits who you are (by age)
- fits your intended use (as a ring, pendent, etc.)

#3 – Factors associated with the HCA.

Getting at these was perhaps the original intent of this thread. It’s fine that it’s wandered. There may be no need to come back here. The idea is that a number of factors have been associated with the HCA, that are probably neither randomly associated with it, nor “one to one” in nature (like, despite it''s essentially linear makeup where low is good and high is bad, head obstruction issues and possibly lighting environment issues, and the like seem to intervene). Some of us are curious. And, if we want to use this tool to help us make a purchase, we may be more than curious. Also, for those who would rather not see a whole spectrum of options scoring 0 – 1 go down the crapper, this may present a renewed focus. Hopefully, someone more able than me will try to address those questions in a thoughtful enough way that some good critical intelligence will be brought to them. But, until such time, I’m guessing that some people will tend to ditch these options (0 – 1) when they may not need to. It’s meanwhile possible that directions in 2b above will satisfy these concerns, and all options scoring 0 – 2 can be considered equally, taking the suggested measures in hand.

Just some thoughts…

How about...

When to use the HCA: Always. Use it as ONE tool amongst many to help you reach an educated decision.

To me that''s the ultimate in K.I.S.S.

 

[Garry H (Cut Nut)]

actually guy''s - page 3 is the tutorial - the place where all the descriptions etc should be.

Thanks for all your help and advice everyone - i hope you are all warmly satisfied that we have answered every possible question

 

[Rhino]

Good job Garry.