17 replies to this topic

[getreal]

Hey all! I'm about to purchase a diamond and I thought I was buying a great diamond until I entered the numbers on the HCA tool on pricescope. It did not do so well because the crown angle and pavilion angle were not a great combination? Should I put any weight into the HCA score? Any advice is greatly appreciated. I think i'm in way over my head!

Here are the specifications.
Cost: $8600
Carat: 1.40
Color: G
Clarity: SI1
Cut: Excellent
Polish: Excellent
Symmetry: Excellent
Measurements: 7.10 - 7.15 x 4.46 mm
Depth: 62.6%
Table: 57%
Girdle: Medium-Slightly Thick
Culet: None
Fluorescence: None
Crown Angle: 36.0
Crown Height: 16.0
Pavilion Angle: 41.0
Pavilion Depth: 43.5%
Star Length: 55%
Lower Half: 80%
Certificate: GIA

[denverappraiser]

The HCA shows the particular bias of it's author in terms of how diamonds 'should' look and it's examining some different criteria than the GIA cut grading scale. I don't find it to be particularly useful in your situation but Pricescope is full of people who swear by it. Personally, I prefer the GIA cut grading scale by a wide margin and the AGS grading scale over that.

Neil

[getreal]

denverappraiser, on Friday, Jul 23 2010, 01:24 PM, said:

The HCA shows the particular bias of it's author in terms of how diamonds 'should' look and it's examining some different criteria than the GIA cut grading scale. I don't find it to be particularly useful in your situation but Pricescope is full of people who swear by it. Personally, I prefer the GIA cut grading scale by a wide margin and the AGS grading scale over that.

Neil

Thanks for your feedback Denver! Based on the description I wrote, is this a good purchase at a fair price?

[davidelevi]

In addition to Neil's ranking (which I entirely agree with, BTW), I'd point out that the HCA does not see the diamond; the people grading it at GIA and AGS do. And they see and measure all the facets and angles, not just use four averages.

On the fair purchase at a fair price - it depends. Most SI1 are eye clean; is this one? Most GIA "Excellent" are quite nice, some are really very nice. Is this one? It's in the top 20% for price when compared to stones listed for sale here (Diamond Finder link at the top of the page), so I'd expect it to be, but we have no way of knowing based on the info you have. Is the stone in stock with someone? Can they call it in and look it over for you (maybe with you)?

[getreal]

davidelevi, on Friday, Jul 23 2010, 02:21 PM, said:

In addition to Neil's ranking (which I entirely agree with, BTW), I'd point out that the HCA does not see the diamond; the people grading it at GIA and AGS do. And they see and measure all the facets and angles, not just use four averages.

On the fair purchase at a fair price - it depends. Most SI1 are eye clean; is this one? Most GIA "Excellent" are quite nice, some are really very nice. Is this one? It's in the top 20% for price when compared to stones listed for sale here (Diamond Finder link at the top of the page), so I'd expect it to be, but we have no way of knowing based on the info you have. Is the stone in stock with someone? Can they call it in and look it over for you (maybe with you)?

I wrote everything down from the GIA certificate report.
Carat: 1.40
Color: G
Clarity: SI1
Cut: Excellent
Polish: Excellent
Symmetry: Excellent
Measurements: 7.10 - 7.15 x 4.46 mm
Depth: 62.6%
Table: 57%
Girdle: Medium-Slightly Thick
Culet: None
Fluorescence: None
Crown Angle: 36.0
Crown Height: 16.0
Pavilion Angle: 41.0
Pavilion Depth: 43.5%
Star Length: 55%
Lower Half: 80%

[davidelevi]

I know you did. The problem is that there isn't enough info on the report to answer those questions. It's a bit like looking for a car, and finding a description that says "Toyota Camry 3000 cc engine, four doors, red, 20,000 miles $8,600". Would you buy sight unseen? And bear in mind that Camries vary a lot less than diamonds!

[getreal]

davidelevi, on Friday, Jul 23 2010, 02:29 PM, said:

I know you did. The problem is that there isn't enough info on the report to answer those questions. It's a bit like looking for a car, and finding a description that says "Toyota Camry 3000 cc engine, four doors, red, 20,000 miles $8,600". Would you buy sight unseen? And bear in mind that Camries vary a lot less than diamonds!

I understand. I saw the diamond for myself and I loved it. I guess I just started second guessing myself because it failed the HCA test on pricescope. People were claiming that it will not sparkle well. Thanks for the advice David!

[davidelevi]

You should have said. A pair of eyes trump any test, device and report known to mankind.

[jan]

getreal, on Friday, Jul 23 2010, 04:17 PM, said:

Hey all! I'm about to purchase a diamond and I thought I was buying a great diamond until I entered the numbers on the HCA tool on pricescope. It did not do so well because the crown angle and pavilion angle were not a great combination? Should I put any weight into the HCA score? Any advice is greatly appreciated. I think i'm in way over my head!

Here are the specifications.
Cost: $8600
Carat: 1.40
Color: G
Clarity: SI1
Cut: Excellent
Polish: Excellent
Symmetry: Excellent
Measurements: 7.10 - 7.15 x 4.46 mm
Depth: 62.6%
Table: 57%
Girdle: Medium-Slightly Thick
Culet: None
Fluorescence: None
Crown Angle: 36.0
Crown Height: 16.0
Pavilion Angle: 41.0
Pavilion Depth: 43.5%
Star Length: 55%
Lower Half: 80%
Certificate: GIA

Based on the numbers, it does look like it has quite a bit if extra fat on the stone such as the smaller diameter, steeper crown angle etc.
The only way to tell if it effects the light performance would be to run it on the brilliancescope.


Keep in the mind that the HCA is not seeing the actual diamond, and is using 4 average numbers to spit out a blind forumula.

You probably picked that stone based on the price and carat weight, color and clarity, however you left out the cut on the stone which really makes up the price of the stone. Remember, you get what you pay for.


I know we have one listed on our site in the same color and clarity however it does run more, and with good reason.

Edited by jan, 24 July 2010 - 06:45 AM.

[denverappraiser]

pgolden, on Tuesday, Jul 27 2010, 04:40 AM, said:

there is a reason why the HCA measure is not an accepted standard in the industry. It is generally considered inaccurate.
I am not saying ignore it, but don't let that be the only factor you base your decision on

I think the reason has more to do with the politics in the industry than with the perception of accuracy. Most people outside of the pricescope community have never heard of it but it's actually pretty clever. The HCA predates both the GIA and the AGS cut grading systems (the current one) and, in my opinion, it was an important part of the evolution of both. This evolution continues and although I think there are now better tools available for consumer shopping purposes but it had it’s day and was extremely useful within it's context, especially given that it's completely free (unlike GIA and AGS cut grades).

Neil

Edited by denverappraiser, 28 July 2010 - 12:55 PM.

[barry]

The perils of "blind" advice.

[denverappraiser]

barry, on Tuesday, Jul 27 2010, 11:58 AM, said:

The perils of "blind" advice.

Agreed.

Neil

[diamondsbylauren]

I agree with Neil and Barry wholeheartedly.
It's obviously misleading that people giving opinions, in the form of blind advice, do so as if it was some sort of scientific fact...
I do disagree with something Jan wrote- you DO NOT need any tool to ascertain a diamond's "light performance"- she mentioned BrillianceScope.
I'm sure that there are dealers who can correlate the way a diamond looks to tools like these- however suggesting one needs the machine or tool to know what a well cut diamond is would mean that human eyes can't see what is beautiful.
Ultimately, the most seasoned graders- for cut- do so based on experience, and eyesight.

Edited by diamondsbylauren, 28 July 2010 - 03:10 PM.

[Britani17]

Well, some consumers do not always know what they are looking at, especially online customers. I have a lot of customers that can not tell a diamond from a CZ until they are side by side. That being said, the Brilliancescope is another consistent tool to show the customers how well cut the diamond is and not just us saying so. Kind of like a GIA report verifies what the stone is and not just the jeweler grading the diamond. The Brilliancescope, combined with seeing the diamond, can help customers ascertain a well cut diamond from a dud.

Edited by Britani17, 30 July 2010 - 07:56 AM.

[jan]

It certainly is alot easier to sell a diamond with no additional information. Especially if your stone doesn't get a good light performance on the brilliancescope. Many don't like to provide the extra info based on the readings that their stones get. You see it is much easier for someone to just say, " this is a great diamond" versus proving it with light performance.

Edited by jan, 30 July 2010 - 01:20 PM.

[diamondsbylauren]

I don't believe any of the trade member would say it's "easy" to sell a diamond. With or without a machine to validate your opinion.

AS I mentioned earlier, if the machine assists sellers in showing clients how to identify certain aspects- such as hearts and arrows, I can see the value.
I disagree with the concept that one needs a BrillianceScope to judge the cut of a diamond. I would make the case that an expert would not need to look at even a GIA report to say a diamond is well cut. The whole point is how it looks- and by that standard, a "laymen" should also be able to appreciate the differences, if shown a few stones of varying cut qualities.

The way to judge a diamond's cut is visual inspection- that means not all people will pick the same stone as the best made. Not everyone likes hearts and arrows- the brightest diamond as judged by machine is not necessarily the best one in the eyes of actual people.
What that means is that a fair percentage of people choosing will prefer a diamond that might look worse on these machines or one that HCA downgrades. Both are based on one type of preference.
I'm not saying there's anything wrong with using the machines to validate cut.
only that you don't need the machine to be able to appreciate- and to select- well cut diamonds in person.

Edited by diamondsbylauren, 30 July 2010 - 01:57 PM.

[Bradley]

The human eye is subjective. Everyone doesn`t have the same eyesight or even the same preferences. What one calls a "great" diamond may not be equal to another. Still, I think many consumers when shown in the proper conditions can "see" what they like. I find it a problem when everyone in the trade is calling the diamond they are selling "great". Online the consumer becomes more subjected to verbal evaluations. I think this is where the brilliancescope can be a great piece of additional information for the internet consumer.

There are many old timers in the trade that haven`t really kept up with the times and todays modern advances. What they may call a "great " well cut stone existed in their time of the 80`s as what was then a decent looking diamond to them. Todays cutting is far more advanced than it was then and the precision in make and light return of diamonds has increased for the better. Much of this from modern day equipment Most of the diamonds from that era are a different caliber than todays goods. Lazare Kaplan was one of the only cutting firms cutting close to todays makes back then, and Hearts & Arrows diamonds weren`t even heard of. Light return wasn`t much of a concern, spready makes or deep makes were rampant.


Brad

Edited by Bradley, 30 July 2010 - 02:14 PM.

[HeartAndStone]

That's a good point Brad.
People are opt to see what they wanted to see, most especially when it comes to flaws.
For me, you'll feel better if you are open to embrace the imperfections of the diamond.
It's alright to have tools, and certifications to see or be convinced by its 'real' beauty.
On the same basis, if mom says it looks good, and then asks how much did I pay for it, and she's happy., then I'm happy...