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Could use advise on this AGS000 RB but HCA only 2.5

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zm

Rough_Rock
Joined
Nov 29, 2003
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Hello Everyone,

First off, sorry for the long post.

I''ve been quietly reading about diamonds on this site/forum and a few others for the past few weeks. I''d like to thank all the great people here, I''ve learned so much in these past few weeks. 4 weeks ago I knew nothing of diamonds.

Much of my reading led me to search for an H&A AGS Ideal 0 graded RB diamond. I read so much about the H&A and decided that''s a feature I want in my stone. More precisely what I''m looking for is 1.2ct G SI1 AGS000 H&A. (probably a very common sought after stone)

I live in Toronto and have to say it''s been very difficult to find what I''m looking for. Many stores I''ve been to, either don''t know what H&A or even AGS is. By far the most popular diamond grading here in Toronto is GemScan. I like AGS because AGS seems to be the most stringent and most comprehensive grading lab especially in terms of Cut. I find it odd that certain websites have a relatively large abundance of AGS000 H&A stones in inventory while B&M stores I''ve been to don''t even know what it is, let alone have one, nevermind several in inventory. A few stores tell me, we don''t have it in stock, but can get it. They however want financial commitment from me just to bring it in - no thanks. I even bought an Ideal Scope, but fear I lack experience to use it effectively. I mention things like IdealScope, Firesope, Brilliance Scope, HCA, the gemoligist/sales at the stores look like a dear in headlights - never heard of these things. Time and again they tell me the cert is what counts, especially the AGS cert.

I''m still hestitant to purchase my diamond from an online vendor.

Anyway, I found a merchant in Toronto that I kind of like. They had a few AGS000 H&A stones and had a stone with my parameters brought in (no charge). I was estatic to even just be able to see a AGS000 H&A stone, boy did it sparkle! I went to see my chosen stone a couple days ago and liked it enough to put a deposit on it. I wrote down the stats off the AGS cert and punched it into the HCA. It only scored a 2.5 to my disappointment.

Here''s the stats on the stone:

1.197ct, G, SI1
6.87-6.89x4.21mm
Table: 55%
Depth: 61.2%
Crown: 34.6%
Pav: 41.1%
$11,600 CDN + GST+PST

What I particularly liked about this stone was the inclusion. Even under a 10x loupe I could not make it out. The gemoligist had to tell me it''s the little white sliver that looks just like a scratch. No black dots inside, no clouds, no feathers, just the little white sliver, sratch looking. Even on the AGS cert, the plot had only a small red cirlce and from the underside it was shown as a red solid line about 3mm long. Oh, and it sparkled quite nice.

Now, the part that bothers me a tad, is the HCA score of only 2.5. I wasn''t expecting this AGS000 to score above 2. See, I don''t have much experience in this field, but know that I want the most sparkling diamond I can get. I don''t know if a HCA of say 1.1 would be noticeably more brilliant than this 2.5 I''m almost going to buy. It''s so hard to be able to compare various stones side by side as AGS000 stones are very hard to come by in Toronto. Nevermind getting picky about a < 2 HCA score.

Then there''s the HCA itself in terms it''s effectiveness of a tool. I don''t mean to disregard Gary Halloway''s work, it might someday be the new AGS of sorts. How much of a difference does the < 2 on the HCA really make when it''s already a AGS000?

I could sure use some words from others more experienced. Should I add a HCA of less than 2 to my wish list and keep looking for my diamond? I''m not in a huge hurry to get one.

This has been quite the interesting and humbling journey thus far.

Many thanks, Zoran.
 
AGS0 doesn't necessarily mean the stone is 'well cut'...it just means that the stone fits within parameters determined by the AGS as 'ideal'...but in reality I have seen stones that are AGS0 that score 4 or even 5 on the HCA--so it's not the end all to be all and guarantees nothing. Just as the HCA score is not the end all to be all. I personally don't think that any *one* tool determines whether a stone is great or not. I would like more than one to corroborate a story.




In this instance, if you change your 41.1 pav angle to 41, the HCA score drops suddenly to 1.8 with EX VG VG VG. Not EX across the board but under 2.0. The HCA seems to penalize for pav angles over 41 with a crown angle of this nature.




I would hope that Garry or Rich or similar would chime in with their thoughts and also hopefully a DiamCalc model so that you can see where (if any) the light leakage would occur in this stone. Maybe that will help you, but it sounds like your mind is already mostly made up.




If it were me, I would continue to look, especially since you aren't in a hurry; but with your constraints on location--you may be happy with what you have found. Also, keep in mind that while you are leery of buying online and note the locale issue, a few people on here have recently purchased from some of the online vendors, and had them ship to a FedEx holding station at the border in NY and then driven to pick up the stone--saving themselves much $$ in taxes. Maybe they can also chime in , or you can ran a search for their info.




Anyway you have a bunch of options--so good luck!
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On 11/30/2003 2:39:58 AM Mara wrote:


I would hope that Garry or Rich or similar would chime in with their thoughts and also hopefully a DiamCalc model so that you can see where (if any) the light leakage would occur in this stone. Maybe that will help you, but it sounds like your mind is already mostly made up.

Anyway you have a bunch of options--so good luck!
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I would raather let others defend HCA, but here is a DiamCalc for your stone with a 41.1 degree pavilion.
I will post one for 41.0 degrees shortly.

AGS 41.1 nov.jpg
 
If you do buy this stone (which will be far better than almost any diamond any of your friends are likely to have seen) then be sure to set it in a high open backed setting so light can get in the back - because it will really help the fire
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AGS 41.0 nov.jpg
 
Just a few thoughts ZM:

1) Try USA Certed Diamonds located outside Toronto. I am a satisfied customer and have no affiliation with them. Tony and Martin are great to work with. They have high-end stuff, educate customers, and know all of the diamond jargon.

2) Look for the few threads on USA Certed Diamonds on Pricescope.

3) I would echo Mara’s idea to have the diamond sent to a NY location if at all possible. I recall reading a thread or two when Canadians went so far as to rent a US PO Box just for the delivery and savings.

4) Keep looking until you are happy. My first diamond was a big mystery since I bought it with a GIA cert. and it was already set. My second diamond was 1.6 (TIC) on the HCA with Ex, VG, VG, and VG grades. My Third diamond was 0.6 (TIC) on the HCA with Ex, Ex, Ex, and VG grades.

GOOD LUCK!
 
I would like to 2nd Gary's comments on pavilion angles at or greater than 41. Of course we are being anal here but *some* stones at 41 and most over (even if it's just .1 degrees over) contributes to a ring of leakage under the table, also known as the *ring of death*
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. Shallower crown angles help eliminate this but is the reason for the >2 on the HCA.




Chances are however that this stone probably is more brilliant than most you have seen and why it does appeal to your eye moreso than others. 41.1 pavilion angles isn't the end of the world and if you're happy with the service, value and diamond and you have decided not to purchase via the net then go with it.




Regards,


Rhino
 
Rhino & Garry--Thanks for shedding some light on the 'over 41' angle idea--I've often wondered what the difference would look like...Garry's DC postings help clear that up for this particular stone. Not TOO much difference in the two DC sims, except for the area in the table seems to have slightly more light reflection?
 
Thank you all for your input. But another question comes to mind now. What would have a better influence on brilliance, a one grade increase in clarity (SI1 -> VS2) *OR* the SI1 with a HCA score of < 2, and would this be a visible improvement even worth discussing?

Increasing the clarity is easier to accomplish/find, but at higher cost, vs. the lower HCA score. I've been told that the nature of the inclusion(s), can impede light return thus affect brilliance, but they could just be trying to sell me a more expensive stone.

It's so hard to do comparisons of these types because merchants just don't have the stones to be able to line them up side by side and see what yields the brilliance improvement and they are far less enthusiastic than half the people on this forum.

I think I've learned too much here on pricescope
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So many choices to make.
 
Poppy cock.
SI1's are just as bright as flawless diamonds.
Some one is spinning you yarns.
 
yeah, i felt that way too.... too much evaluation and knowledge to make a decision... Let your eyes do it for you.

As far as I know you have to have one messy diamond for it to affect brilliance, ie. in or below the I1-I3 range. Si1's (depending on the stone) are nice and so are VS2s.

I purchased a VS2 with an HCA of 2.7 I think it looks great. However, i looked at an SI H&A which I'm sure had a much lower score and i would say the lower score is better... however, there was price... the SI H&A was over $1,000 US more.

I don't know the exchange rate nor the canadian diamond market, but my feeling is if you're paying the premium for the H&A I'd check and see if you could get one with a lower HCA... Actually I take that back... I think you should LOOK at one with a lower HCA... HCA is helpful, but it isn't the be all and end all, same with any other test. When I looked i was shown the idealscope and the brilliancescope. Those are what sold me on my diamond. It showed me very little leakage and a side by side comparison of two diamonds in different lights. Comparison is key!

And if all else fails take a trip!
 
Hi Zoran,

If you like the stone, get it. Having said that, I think you can get an even nicer stone for your money.

Here's a little advice from a fellow Torontonian whose e-ring was purchased, sight unseen, from an American company, on the internet: buy your stone, sight unseen, from an American company, on the internet.
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In all seriousness, I began searching for diamonds last summer in Toronto. Encountered a wealth of GemScan certs, and not too many GIA/AGS certs. There just isn't enough of a demand up here for retailers to justify the expense of having them readily available in their inventory.

You will have a much better chance of finding the stone you want online, and you will very likely save some $$$ on the deal. In order to avoid paying the hideous taxes and duties, you can get it shipped to a FedEx holding station across the border. Most online vendors have full return policies ranging from 7 to 30 days - and that timeframe begins from the moment you accept delivery of your stone. Point being, there's ample time to eyeball the stone in that return window, and have it appraised independently.

You will find that there are many B&M vendors in the Toronto area who either cannot or will not provide crown and pavilion angles, and it therefore becomes difficult to gauge cut quality. If you are going to continue searching offline, I would recommend that you learn how to use the Ideal-Scope correctly. It is a terrific tool for visually assessing light leakage. Just keep in mind - white/pale pink equals bad, dark pink/red equals good.
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Best of luck with your search.
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On 11/30/2003 2:28:44 AM zm wrote:





I've been quietly reading about diamonds on this site/forum and a few others for the past few weeks. I'd like to thank all the great people here, I've learned so much in these past few weeks. 4 weeks ago I knew nothing of diamonds.

I'm still hestitant to purchase my diamond from an online vendor.
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Hi, Zoran.....welcome to PS!

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Your opening line above made me smile......if you think you've learned a lot in 4 weeks.....stick around! I've been here regularly for more than a year now, and I'm still learning every days. This is highly addictive.



Regarding the stone you asked about, the reason it scored above a 2 is because your pavilion angle is 41.1. The HCA penalizes stones that score above a 40.9, and several of the vendors I've spoken with concur that 41 and up distorts the pattern. AGS 0 proportions call for a range between 40.15 and 41.20 on the pavilion angle, but the original H&A pattern was cut for the 40.9 angle. Interestingly, many will also tell you that they won't go below 40.6 (also due to distortion), so you may want to consider this in looking for a stone that scores well (and performs well).



Lastly......regarding your hesitation on online vendors. When my (now) fiance and I first started talking a year ago about what kind of diamond I might want and where to get it, we both were *adamantly* against the internet due to trust issues. I decided to do some "reconaissance" and wound up here. Found a bunch of nice folks, knowledgable appraisers, and top-rate vendors who are trustworthy.



My fiance and I made the engagement "official" last week, so I'm now in the position of shopping for the diamond, and I can tell you that I unequivocally won't buy anywhere else BUT online now. Do some reading....get on the horn with a few of these vendors......I'd bet my car that you'll come away feeling the same.



Above all else.....do what you're most comfortable with. Select the stone that makes YOU (and her) happy, and do the homework prior to purchase. If you do those things, you can't go wrong.



Best of luck, and let us know if we can help.

 
Congrats AL!
rodent.gif
Buy that stone already would ya?
 
Isn't it cool to see her type "my fiance" ?!!!
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Canadiangrrl, giddy for Aljdewey
 
YAY.......me, too.




Can't get OVER the dopey smile I sport every time I type it or say it!




Some things in life are priceless!
 


Gary,



I have been trying to learn as much about diamonds as I can to buy a diamond, so please be patient with this newbie question....



I have downloaded a copy of DiamCalc and GemAdvisor. The docs say that GemAdvisor reads *.gem files made in Diam calc. How do I make a .gem file using DiamCalc (the demo version)? For the life of me, I can't figure it out...



Right now, I have an AGS cert for an AGS000 diamond, D colour, VS1, 0.855 carats, 56% table, 61.9% depth percentage, 34.9% crown angle, 41.1% pavilion angle, (15.4% crown, 43.3% pavilion), pointed culet, faceted girdle 1.5 % to 2.1%. Is that enough info to plunk into DiamCalc?



RWW



(Basically, I saw that the HCA value was 2.8 and that seems to imply a lot of light leakage in the table area. I think that is what this thread implies. Sorry, but I'm just a techy computerguy (not a diamondguy).)





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On 11/30/2003 5:43:02 AM Cut Nut wrote:





If you do buy this stone (which will be far better than almost any diamond any of your friends are likely to have seen) then be sure to set it in a high open backed setting so light can get in the back - because it will really help the fire
1.gif

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