How much more $ is a better HCA rating?Urgent advice needed

[nelly81]

Hi everyone,

I am desperately seeking urgent responses for choosing a diamond!! I am hoping to get as much feedback as possible as I would like to buy in the next day or two.

I can see that some posts get more replies than others, so I do hope that my post gets some thoughts!! PLEASE as I do not know who please to ask!

My initial budget was $20K all up (and happy to go up a bit if the stone was right as I know this is a lifetime investment!)

I have found my ideal diamond in America (as I am from Australia) – everything looks perfect!

G 1.5 SI1 AGS 000 certified and confirmed as eye clean and a H&A. So much info has been provided on this stone so there are no concerns – ideal scope, brilliance scope etc and comments from other PS users have confirmed it as a gorgeous stone!!! The seller is highly reputable on PS so completely trusted with full refunds as well.

The HCA scored a 1.5 (Excellent) which excellent ratings on all sections except the spread which was very good (7.40 * 7.44 diameter)

Being in Australia – this stone will end up costing me $19,500 (aust $) for the stone alone plus approximate $1500 costs for the band totalling $21,000. The US price is $16,800 but the 10% tax and duties I need to pay to import the stone plus the poor conversion rate when completing an international wire transfer have just exacerbated the problem!


I have also looked at another stone – F 1.51 S12

This stone is sourced locally and I have been able to look at it – it is completely eye clean which is fantastic – the colour is gorgeous and white and it appears to perform greatly.
AND the price of stone including the band is $15,100 (compared to $21,000) aust $
The stone itself is priced at $14,200 and the band in white gold is $900.

However, I am not an expert in determining if a stone is in fact performing great or not being an amateur! I am concerned that it is probably not performing that great at all based on the stats.(shown below) but I just can’t tell.

Here are the stats:

F SI2 1.51 (7.34 * 7.37 * 4.57) GIA certified
Table: 57%
Crown angle: 35 (15.5%)
Pav angle: 41 (43.5%)
Depth: 62.1
Medium facted girdle 3.5

Triple excellent, no flouro

HCA rating: 2.4 (Very Good if the price is right) Very good rating along all the factors
I do not have any idealscope images for this stone. I may try to get my hands on the idealscope tool and view the stone through that although I am not an expert in interpreting the light images.

Is there anything majorly bad in the measurements meaning I should avoid this stone?
When playing around with the HCA tool, it appears that the pav angle impacts the rating the most?
Or maybe the stone is too deep?
Not sure if there will be a lot of light leakage with this stone?

I know it is a bit smaller in size (7.4 vs 7.40 of the other stone) but I do not know that this will be visible once set so not a great concern? Unless you think it should be?

NOW: here is where I need the advice.
I think technically based on the stats, the G 1.5 stone is better, and I also have more info on the stone which has been confirmed as fantastic by PS users.

However, I am really concerned that based on all the extras I need to pay as an Australian customer to import a stone into the country, I am technically OVER paying for the stone (as its value in the US is $17,000 but I am paying almost $20K).

So what I am really asking is – is the better HCA rating and cut specs that I know technically are likely to improve the fire, brilliance and sparkle of the stone worth the extra $5,000 versus the other stone?

Will the difference in performance (based on the specs I have provided for the second stone) be noticeably different to justify the extra $5000 to a normal person?

I am concerned that I may be over eager to purchase the cheaper stone as it the cleanest SI2 I have seen!! And I am so fussy with inclusions!!! But then again, maybe it is so much cheaper because it is a poor performing stone and is not that great a deal!!!

Even though the other stone is more, it is still within my original budget (or just over) of $20k so I will spend it if required. I just want to ensure I am not paying more for no reason that produces no visible benefit (just specs).

I must say – knowledge in regards to HCA ratings and idealscope images is non existent in Australia so when you mention it, they really have no idea what you are talking about and seem to purely focus on the triple excellent ratings of certificates instead! This makes it even more difficult!!! Furthermore, the availability of stones is not as good in America which makes the selection process so limited. I have had a bad experience in importing what was apparently an eye clean SI1 that really had only one major inclusion that just happened to be BLACK, therefore I returned it. So I am very cautious!

This is a once in a lifetime expensive purchase, so I just want to do the right thing! Am I completely over thinking it and considering things that I ultimately won’t see??? All my friends think I am nuts! But they obviously haven’t gone on Pricescope forums.

Please let me know if you would like me to provide any further information to assist with any advice.

Please tell me what you would do in this instance if you were in my position?

Thanks in advance!

Nelly

 

[ZahraLeyla]

Re: How much more $ is a better HCA rating?Urgent advice nee

I can't comment re: the diamonds, but having purchased a diamond from the US via wire transfer previously, I can highly recommend using OzForex. They offer the best exchange rates going around. Good luck with your purchase.

 

[Christina...]

Re: How much more $ is a better HCA rating?Urgent advice nee

I certainly can't make the decision for you, but I can say that I believe that the difference between an HCA of 1.5 and 2.4 will be noticeable. From there you will have to decide whether or not the difference in light performance is worth the difference in savings. Is it possible to continue you search in Australia?

 

[wakingdreams53]

Re: How much more $ is a better HCA rating?Urgent advice nee

So basically, you're choosing between a GIA Triple X and an AGS0. Cut wise, you're fine. I'd say you're safe ignoring the HCA because there are beautiful 2+ stones out there and since you saw it in person, you know that for yourself.

The HCA doesn't take into account other important facets. As it says a good million times on this website, HCA is a rejection tool not a selection tool. It can't tell you which stone will be better.

And size wise, a difference of 0.06? You're talking less a tenth of a millimeter. Don't sweat it, seriously.

Go by your eyes. The G AGS0 sounds great, but you've got an F GIA triple X at home! No shipping, customs, duties, headaches!
If I were in your position, I would stop second guessing myself. You saw the stone, it looks great. If you're still unsure, buy yourself a beginner idealscope and see for yourself. http://www.ideal-scope.com/cart_order.asp

This is a huge purchase and you've already put a lot of time and research into it. Don't get disheartened yet!

Note: You post was a little daunting in size, which is probably why you don't have more responses.

 

[stone-cold11]

Re: How much more $ is a better HCA rating?Urgent advice nee

Depends, mainly because the measurements used by the HCA are average of 8 measurements and rounded significantly by GIA, 0.2 in the pavilion angle and 0.5 in the crown angle, that can result in significant difference in performance which is why idealscope is usually the next step.

 

[Rockdiamond]

Re: How much more $ is a better HCA rating?Urgent advice nee

Basically, HCA is , in some ways like oxygen.
It costs nothing.
And you can't see it.

Seriously- If you're looking at the diamonds, ignore HCA.
It has virtually no impact on the price of a diamond, unless a seller is trying to get more for a stone that scores well.
Based on physical characteristics, you may very well prefer a stone graded EX cut grade with a lower HCA score than a second GIA EX with a better HCA score.

 

[slg47]

Re: How much more $ is a better HCA rating?Urgent advice nee

Will the difference in performance (based on the specs I have provided for the second stone) be noticeably different to justify the extra $5000 to a normal person?

I am concerned that I may be over eager to purchase the cheaper stone as it the cleanest SI2 I have seen!! And I am so fussy with inclusions!!! But then again, maybe it is so much cheaper because it is a poor performing stone and is not that great a deal!!!

Even though the other stone is more, it is still within my original budget (or just over) of $20k so I will spend it if required. I just want to ensure I am not paying more for no reason that produces no visible benefit (just specs).

I must say – knowledge in regards to HCA ratings and idealscope images is non existent in Australia so when you mention it, they really have no idea what you are talking about and seem to purely focus on the triple excellent ratings of certificates instead! This makes it even more difficult!!! Furthermore, the availability of stones is not as good in America which makes the selection process so limited. I have had a bad experience in importing what was apparently an eye clean SI1 that really had only one major inclusion that just happened to be BLACK, therefore I returned it. So I am very cautious!

there is no way to know if it is worth it to you, unless you can compare both in person (which you cannot do).

what are the inclusions in the SI2?

can you possibly take the stone to an independent appraiser? or compare it to other stones in the store (maybe AGS0s, or GIA Ex with HCA <2) to see what you like better?

 

[nelly81]

Re: How much more $ is a better HCA rating?Urgent advice nee

Hi there,

the inclusions are some twinning wisps that are eye clean. the GIA cert number is 2126548754 if you want to take a look.

should I be concerned with the twinning wisps?

What do you think of the specs? crown and pav angle? depth? table?

Any major concerns that are likely to impact the appearance??

 

[nelly81]

Re: How much more $ is a better HCA rating?Urgent advice nee

as mentioned above, twinning wisps are the main inclusion in the SI2. Do they impact the durability of the stone?

 

[garmando]

Re: How much more $ is a better HCA rating?Urgent advice nee

Buy the stone at home. $5000? That's a huge increase for a stone you haven't seen. You are already excited with a stone you have seen with your own eyes. Like the post said above, stop second guessing yourself.

 

[kindred]

Re: How much more $ is a better HCA rating?Urgent advice nee

Get an ideal-scope and use it to check out the local stone.

 

[tenyearanniversary]

Re: How much more $ is a better HCA rating?Urgent advice nee

I would get the one at home. I've looked at alot of RB's lately, and the difference between a 1 and a 2+ HCA is a little noticeable if you really look for it, but then again not noticeable to the average person at all. I've seen some nice stones that are 3's also. Depends how nit picky you want to be. I don't think it's worth the extra money. Or maybe look for an AGS ideal cut locally if you have the time to look more.

 

[Rockdiamond]

Re: How much more $ is a better HCA rating?Urgent advice nee

Guys- it's very confusing to have a tool that gives numerical numbers that do not mean what you think they do.
A 1 is NOT better than a 3- except in Garry's eyes.

Ten year- I have no doubt you noticed differences between stones- but the differences you noticed can not be correlated to HCA.
There have been to many cases to count where I preferred a GIA EX cut grade that scored below 4 over a stone scoring a better HCA score.
Plus- the comments like "buy only if the price is right" is not in touch with the real world. No diamond seller I've ever heard of will discount a GIA EX cut grade because of a low HCA score.

Nelly- I totally feel for you.
It's natural to want guidance in such an important decision- and it might seem that HCA ( or ideal scope) offers definitive , easy answers.
Neither does, in your case.

BUT- you have seen the stone in person- that's 10000% more important than anything written here. Remember, there's different appearances possible within GIA EX cut grade ( or AGSL0)
Someone reading this, and posting- may have a strong view- but it might not match what you love with your own two eyes.

Personally, I love SI2's that are eye clean.
They save you a ton of money for something you can't even see.

 

[nelly81]

Re: How much more $ is a better HCA rating?Urgent advice nee

Hi RockDiamond,
Thanks for all of your words!!
Is there anything in the measurements that I have provided that are generally not great? ie crown angle, pav angle, depth, table etc?
I will view the stone again? is there anything I should look out for in particular that shows the stone isnt performing great? I dont really know what to look out for?
Any particular lighting conditions?
Thanks! Nelly!

 

[yssie]

Re: How much more $ is a better HCA rating?Urgent advice nee

Hi RockDiamond,
Thanks for all of your words!!
Is there anything in the measurements that I have provided that are generally not great? ie crown angle, pav angle, depth, table etc?
I will view the stone again? is there anything I should look out for in particular that shows the stone isnt performing great? I dont really know what to look out for?
Any particular lighting conditions? Thanks! Nelly!

YES!

If you are able to see and compare in-person, I too recommend trusting your eyes - it's your eyes that must appreciate all the nuances of *that* particular stone, afterall! We use all these tools when we're buying blindly online to try to help us narrow it down to stones our eyes will like. You, by choosing in-person, can skip all that narrowing down and jump straight to "which one takes my breath away"

When you're in-store be sure to compare several stones in different types of lights - there is a surprising variety in-store! Have them clean all the stones (and then be sure not to touch them without tweezers!), then take them around and look under the spotlights in the counters of course, in the diffuse back-office lights, in a beam of direct sunlight by a window, in the dimness under a desk... you'll find that some lights bring out inclusions more than others as well, since you're looking at lower clarities you'll want to confirm the stone is clean to your personal requirements in all sorts of lighting types. Then get them dirty - just get your fingerprints all over, and walk through those same rooms again, see what you think this time...

 

[crbl999]

Re: How much more $ is a better HCA rating?Urgent advice nee

Hi RockDiamond,
Thanks for all of your words!!
Is there anything in the measurements that I have provided that are generally not great? ie crown angle, pav angle, depth, table etc?
I will view the stone again? is there anything I should look out for in particular that shows the stone isnt performing great? I dont really know what to look out for?
Any particular lighting conditions? Thanks! Nelly!

YES!

If you are able to see and compare in-person, I too recommend trusting your eyes - it's your eyes that must appreciate all the nuances of *that* particular stone, afterall! We use all these tools when we're buying blindly online to try to help us narrow it down to stones our eyes will like. You, by choosing in-person, can skip all that narrowing down and jump straight to "which one takes my breath away"

When you're in-store be sure to compare several stones in different types of lights - there is a surprising variety in-store! Have them clean all the stones (and then be sure not to touch them without tweezers!), then take them around and look under the spotlights in the counters of course, in the diffuse back-office lights, in a beam of direct sunlight by a window, in the dimness under a desk... you'll find that some lights bring out inclusions more than others as well, since you're looking at lower clarities you'll want to confirm the stone is clean to your personal requirements in all sorts of lighting types. Then get them dirty - just get your fingerprints all over, and walk through those same rooms again, see what you think this time...

Ditto. Well said.

 

[Garry H (Cut Nut)]

Re: How much more $ is a better HCA rating?Urgent advice nee

Hi RockDiamond,
Thanks for all of your words!!
Is there anything in the measurements that I have provided that are generally not great? ie crown angle, pav angle, depth, table etc?
I will view the stone again? is there anything I should look out for in particular that shows the stone isnt performing great? I dont really know what to look out for?
Any particular lighting conditions? Thanks! Nelly!

YES!

If you are able to see and compare in-person, I too recommend trusting your eyes - it's your eyes that must appreciate all the nuances of *that* particular stone, afterall! We use all these tools when we're buying blindly online to try to help us narrow it down to stones our eyes will like. You, by choosing in-person, can skip all that narrowing down and jump straight to "which one takes my breath away"

When you're in-store be sure to compare several stones in different types of lights - there is a surprising variety in-store! Have them clean all the stones (and then be sure not to touch them without tweezers!), then take them around and look under the spotlights in the counters of course, in the diffuse back-office lights, in a beam of direct sunlight by a windowthis is never a good test because most of the best cuts perform badly in such lighting - if you do this test then stand with your back to the sun and look at the diamond in your shadow - but there are many influencing factors such as the brightness of the background behind you (blue sky? Clouds? etc and the background behind the stone - is it light or dark? completely different results - so best never ever to use direct sunlight - and please folks who have seen all the trheads like "my diamond looks dark in direct sunlight" remeber that it is the point light effect and not really about the diamond. , in the dimness under a desk... you'll find that some lights bring out inclusions more than others as well Difused lighting is best to see inclusions , since you're looking at lower clarities you'll want to confirm the stone is clean to your personal requirements in all sorts of lighting types. Then get them dirty - just get your fingerprints all over, and walk through those same rooms again, see what you think this time... that only makes the top of the stone dirty - but if you can make the pavilion dirty then that is the best test. One way to do that with a loose stone is press it into some blu tac - I forget the US product name - its a 3M plasticine like stuff for putting posters on walls.

Ditto. Well said.

 

[Karl_K]

Re: How much more $ is a better HCA rating?Urgent advice nee

Here are the stats:

F SI2 1.51 (7.34 * 7.37 * 4.57) GIA certified
Table: 57%
Crown angle: 35 (15.5%)
Pav angle: 41 (43.5%)
Depth: 62.1
Medium facted girdle 3.5

The gia numbers averaged then rounded are not accurate enough to evaluate this diamond.
It may be fine it may have some dark zone leakage under the table that may or may not be visible.
Typical jewelery store lighting will hide this darkness.
Take it into a living room lit by cft lighting and it may become visible.
The move to cft lighting is making this more of an issue.
But again I stress the GIA numbers are not accurate enough to say if this is the case!

 

[Karl_K]

Re: How much more $ is a better HCA rating?Urgent advice nee

as mentioned above, twinning wisps are the main inclusion in the SI2. Do they impact the durability of the stone?

This is another case of it might or might not be an issue, we cant tell you.
What happens is in some lighting they can make the diamond murky because they scatter the light.
It looks like the diamond is foggy.
The do reduce the value of the stone either way.

I was just talking to a friend the other day.
They replaced the lighting in their home to save electricity costs.
Her diamond started looking murky.
She had not noticed it for 10 years.
Had it cleaned twice, still murky when looking at it just so in her living room.
Yep si2 twinning wisps.
But there is no way for us to tell you if the diamond you are considering has this problem without looking at it.
Frankly I can't give you advise about this stone, way to many unknowns.

 

[Rockdiamond]

Re: How much more $ is a better HCA rating?Urgent advice nee

You're welcome Nelly!
One of the great things about this forum is how it allows an array of viewpoints from professionals- and there can be differences of opinion.
For example: Twining Wisps- here's my experience:
In a stone graded SI2 by GIA, twining wisps are virtually never a consideration with regard to durability.
Even the visual aspects are generally not bothersome.
Based on GIA's methodology of clarity grading, an SI2 sized amount of twining wisps are more likely to be totally invisible without a loupe as they are to cause any sort of cloudy condition.

Another area where disagreement might be illuminating to consumers is a statement Karl made:

The gia numbers averaged then rounded are not accurate enough to evaluate this diamond.
It may be fine it may have some dark zone leakage under the table that may or may not be visible.
Typical jewelery store lighting will hide this darkness.
Take it into a living room lit by cft lighting and it may become visible.
The move to cft lighting is making this more of an issue.
But again I stress the GIA numbers are not accurate enough to say if this is the case!

I have never had one single problem- ever- due to GIA rounding numbers.
AS a diamond designer, Karl has different considerations than a diamond dealer.
I look at the diamonds, judge the quality of cut, and make up my mind.
In my opinion a diamond can never be properly evaluated based solely on measurements- regardless of averaging and rounding of numbers.
Then we have the issue of "leakage"
Again, for those interested in highly technical discussion, leakage might be interesting.
For a consumer who does not wish to become a diamond designer, it's completely a moot point. Besides that, both these issues sound quite serious to an uninitiated consumer.

Nelly- please don't let all this discussion scare you.
If there was any issue with a diamond, and you observe it as has been suggested here, you'd see that problem.
I'm still waiting to se a GIA EX cut grade diamond with "problem leakage"

 

[Garry H (Cut Nut)]

Re: How much more $ is a better HCA rating?Urgent advice nee

I will throw in another professional opinion.
Many diamonds today that are graded SI2 would have been graded as I1 a decade or two ago. There have been supporting small surveys done where old stones have been resubmitted and got higher grades.
In sizes over 1/2ct the chance to see inclusion in SI stones or have other deleterious impact rises as the size rises. At 1.5ct there are few stones that you should buy without some protection from either a vendor on your side - and especially or an appraiser.

Now lots of people will come on and say "I bought a beauty at a great price".
1. that can be true
2. they may not know what a good appraiser would tell them (and they should just remain happy)

So in short, I think there would be maybe <10% of SI2's that I would offer to clients in a ring, and maybe 30% that I would suggest for earrings or pendants in 1.5ct sizes.
Even in SI1 I would expect to be able to see many inclusions in +1ct stones.
As I often post -be more aware of clouds and things that dull the passage of light in stones with few easily located inclusions under 10X loupe examination.

 

[quaddio]

Re: How much more $ is a better HCA rating?Urgent advice nee

I'm very concerned you're being pressured to make a decision about the local diamond.

I'm an Australian living in US and if I were in your shoes I'd buy the online stone and have it shipped. Pricescope vendors have so much going for them in terms of upgrades, return/exchange policies and economies of scale. The price increase is worth it to buy with a lower risk with flexibility down the line.

As an aside, if the cost of shipping/customs is getting out of hand don't rule out traveling to the states and buying in person. At some pricepoint you'd be ahead with this option.

To threadjack, my Australian friends always have me bring cosmetics, clothes, electronics when I go back. A close friend may have me buy/deliver his FI's ring when I visit later this month! He was unhappy with Australian selections in the $5-7k range.

 

[Karl_K]

Re: How much more $ is a better HCA rating?Urgent advice nee

You're welcome Nelly!
One of the great things about this forum is how it allows an array of viewpoints from professionals- and there can be differences of opinion.
For example: Twining Wisps- here's my experience:
In a stone graded SI2 by GIA, twining wisps are virtually never a consideration with regard to durability.
Even the visual aspects are generally not bothersome.
Based on GIA's methodology of clarity grading, an SI2 sized amount of twining wisps are more likely to be totally invisible without a loupe as they are to cause any sort of cloudy condition.
I have seen it with my own eyes as posted above. We have also had examples posted here when the gemologist was asked to check the stone they reported it was foggy/murky. I have talked to dealers who have seen the same thing and rejected stones because of it. si2 wisps are a crap shoot.

AS a diamond designer, Karl has different considerations than a diamond dealer.
I was a diamond consumer a long time before I was a designer and still am when I am shopping for a sparky for my wifey4ever :}
I look at the diamonds, judge the quality of cut, and make up my mind.
In my opinion a diamond can never be properly evaluated based solely on measurements- regardless of averaging and rounding of numbers.
nice way to spin what I said.... read it again

Then we have the issue of "leakage"
Again, for those interested in highly technical discussion, leakage might be interesting.
For a consumer who does not wish to become a diamond designer, it's completely a moot point. Besides that, both these issues sound quite serious to an uninitiated consumer.
it is a point for the consumer who takes it home and sees the dark zone in their living room under cfl lighting

 

[nelly81]

Re: How much more $ is a better HCA rating?Urgent advice nee

Hi quaddio,
Thanks for the tip! But I thought you still had to pay tax and duties even travelling (not just shipping)?? My friend is in the states at the moment but I thought he would still have to declare any goods over $1000 upon arrival in Australia?

What is your experience?

Cheerss, Vanessa

 

[nelly81]

Re: How much more $ is a better HCA rating?Urgent advice nee

Hi Kark K,
Thanks for your comments? I have two questions.
What is cfl lighting?
You referred to SI2 wisps as a 'crap shoot'? Can you please explain what you mean? It sounds negative!! )

Cheers

 

[nelly81]

Re: How much more $ is a better HCA rating?Urgent advice nee

Hi Garry,

Your point is interesting and has made me think further in regards to what I viewed through the loupe. I have seen one other stone with twinning wisps. When viewing that stone though the loupe, i could easily see the wisps (it almost looked like the stone has been engraved!). However, they could not be seen with the naked eye.

However, when viewing this stone, I could not believe how eye clean it was! Almost no inclusions visible through the loupe for an SI2? I could hardly even spot the wisps like I could on the other stone!!! The wisps on the other stone seemed to be significantly more severe.

Is that a concern? As you mentioned in your comments, if the inclusions on an SI2 cannot be seen through a loupe, is is likely that these wisps (plus the additional wisps and graining mentioned in the comments section) are likely to impact the appearance of the stone and overall performance? To be honest, I still cant believe how clean it looked through the loupe compared to the Si1 and SI2 stones have seen?
It makes it surprising that it is graded as a SI2? Unless the effects other visible other ways!??

As an amateur, it is so hard to tell if there are issues in the appearance without knowing specifically what to look for? In the end, every diamond looks sparkly to a rookie - of course direct comparison of stones with superior cuts will no doubt show a difference. I just wonder how much to justify the price difference??

Comments?

Thanks!!! )

 

[stone-cold11]

Re: How much more $ is a better HCA rating?Urgent advice nee

Hi Kark K,
Thanks for your comments? I have two questions.
What is cfl lighting?
You referred to SI2 wisps as a 'crap shoot'? Can you please explain what you mean? It sounds negative!! )

Cheers

CFL = Compact Fluorescent Light.

By crap shot, Karl meant that it can be good or bad, a shot in the dark, if you are lucky, you might get the few eye-clean ones, most of the time you will not.

 

[stone-cold11]

Re: How much more $ is a better HCA rating?Urgent advice nee

As an amateur, it is so hard to tell if there are issues in the appearance without knowing specifically what to look for? In the end, every diamond looks sparkly to a rookie - of course direct comparison of stones with superior cuts will no doubt show a difference. I just wonder how much to justify the price difference??

The point is since it is sold as a GIA Ex cut, there will be little if any price difference between this stone and one cut slightly shallower in the pavilion, since as RD says, most jewelers do not use HCA score to price diamonds. So if there is a difference in performance and the price is about the same, why not buy the better performing one?

That said, as many of us have said before, the numbers are slightly iffy on the performance issue due to the averaging and rounding of numbers by GIA. GIA could have rounded the numbers in a bad way for this stone, from CA of 34.8 to 35, and PA of 40.91 to 41, result in a worse score than it would have gotten. Or it could be the other way round, CA 35.2 to 35 and PA 41.09 to 41, then it will have a worse performance than predicted by HCA.

 

[Rockdiamond]

Re: How much more $ is a better HCA rating?Urgent advice nee

I will throw in another professional opinion.
Many diamonds today that are graded SI2 would have been graded as I1 a decade or two ago. There have been supporting small surveys done where old stones have been resubmitted and got higher grades.
In sizes over 1/2ct the chance to see inclusion in SI stones or have other deleterious impact rises as the size rises. At 1.5ct there are few stones that you should buy without some protection from either a vendor on your side - and especially or an appraiser.

Now lots of people will come on and say "I bought a beauty at a great price".
1. that can be true
2. they may not know what a good appraiser would tell them (and they should just remain happy)

So in short, I think there would be maybe <10% of SI2's that I would offer to clients in a ring, and maybe 30% that I would suggest for earrings or pendants in 1.5ct sizes.
Even in SI1 I would expect to be able to see many inclusions in +1ct stones.
As I often post -be more aware of clouds and things that dull the passage of light in stones with few easily located inclusions under 10X loupe examination.

I think there's an easy explanation for the difference in our opinion Garry.
How many 2ct plus stones come into Australia for dealers?
How many come into NYC?
I'd say for every 2ct stone coming into Australia, there's 100 coming into NYC.
So the available pool here is so much greater- that your experience about how many of those stones are eye clean will be impacted by the limited pool of stones available.
I know that when I look for SI2's to buy- I like to shop when cutters just re-stocked their boxes.
Seems the same Si2 dogs stay for years- while the eye clean SI2's get snapped up pretty quickly.
This too affects the percentage of eye clean stones in a the general pool of stones.
However none of this is applicable if someone is looking at actual SI2 diamonds.
Put another way- if I'm buying an eye clean SI2, what difference does the overall percentage of eye clean SI2 diamonds make?

General statements made when someone is asking about a specific diamond can be ( and obviously are) misleading.

Nelly if the diamond you've seen is clean and clear to your eye, please don't let discussion of Si2 diamonds in general affect your selection process.

With regards to Quaddio's comment ( I don't think it was directed at me) - please don;t mistake my comments as an endorsement of any given stone.
Rather they are true (imo) for whatever stone you're looking at- from whatever vendor

 

[Karl_K]

Re: How much more $ is a better HCA rating?Urgent advice nee

Hi Kark K,
Thanks for your comments? I have two questions.
What is cfl lighting?
You referred to SI2 wisps as a 'crap shoot'? Can you please explain what you mean? It sounds negative!! )

Cheers

CFL = Compact Fluorescent Light.

By crap shot, Karl meant that it can be good or bad, a shot in the dark, if you are lucky, you might get the few eye-clean ones, most of the time you will not.

Thanks Stone that is correct.
My time to spend on the forum is kinda sporadic lately, sorry about the late reply.

We get kind of spoiled here with the stocking dealers who have already rejected the worst of the si1/si2 diamonds for stock. They do not represent what is out there on the lists and in the rest of the world.
That is why you see varying opinions on them.