Buying blindly - what could possibly go wrong

[babydoll_mini]

Hi Experts,

Newbie here, and I have a desperate question about buying blindly (without seeing any pictures of the actual stone) from vendors like BlueNile. This question actually popped to me while I'm reading another thread:

oh he's a clever one - just enough truth to make you wonder if there's something to the BS


https://www.pricescope.com/journal/laboratory_cut_grades_what_report_doesn%E2%80%99t_show will show you a little more about why it is better to look at a stone and judge for yourself than blindly trust in a (for-profit, indeed) corporation's say-so.

Newbie here, strange enough, after reading this article, I think it is Totally Fine to buy RB stone (esp. smaller ones < 1ct maybe) blindly from vendors like BlueNile...

Just stick with the most strict criteria of proportions will do, for example:
table: 56-57
depth: 60.8-61.8
pa: 40.6-40.8
cr: 34-34.5
st: 55
lh: 75
girdle: medium

My reasoning is as following: among the example stones used in that article, all the good looking ones( 2, 6, 8 ) falls in the criteria above and the rest fails the criteria...
So even with a less-precise GIA cert, if we stick with the most strict criteria in proportion, and with the extra help of HCA, what could possibly go wrong even if one is purchasing blindly?

If my reasoning is correct, why should we pay extra money for the idealscope/aset image, or further review while buying RB ?
Am I missing anything?

I'd like to ask whether there's still possibility that things can go wrong even if all the "numbers" are ideal?
Thank you!!

 

[yssie]

this was discussed in another thread just a couple weeks back, should help answer your q: [URL='https://www.pricescope.com/community/threads/big-favour-to-ask.152604/']https://www.pricescope.com/community/threads/big-favour-to-ask.152604/[/URL]

 

[babydoll_mini]

this was discussed in another thread just a couple weeks back, should help answer your q: [URL='https://www.pricescope.com/community/threads/big-favour-to-ask.152604/']https://www.pricescope.com/community/threads/big-favour-to-ask.152604/[/URL]

Hi Yssie, thank you for you reply, I think you are referring to the following thread as an example of what could go wrong with perfect stats.
[URL='https://www.pricescope.com/community/threads/diamond-should-i-bite.144057/']https://www.pricescope.com/community/threads/diamond-should-i-bite.144057/[/URL]

This stones does not score well on HCA though:

 

[yssie]

No I am referring to the thread I linked, read the q about halfway down the page - it asks exactly the same thing as your thread title.

That stone scores 'fine' on the HCA - under 2. In any case, don't try to select using the HCA - it's not designed as a selection aid.

 

[babydoll_mini]

No I am referring to the thread I linked, read the q about halfway down the page - it asks exactly the same thing as your thread title.

That stone scores 'fine' on the HCA - under 2. In any case, don't try to select using the HCA - it's not designed as a selection aid.

Yeah, sorry, I just realized I have paste the wrong url. I've edited my reply.
But actually the HCA has anticipated that it is not a top "light return" performer right?
So not a surprise that it has some leakage under the table?

 

[yssie]

No I am referring to the thread I linked, read the q about halfway down the page - it asks exactly the same thing as your thread title.

That stone scores 'fine' on the HCA - under 2. In any case, don't try to select using the HCA - it's not designed as a selection aid.

Yeah, sorry, I just realized I have paste the wrong url. I've edited my reply.
But actually the HCA has anticipated that it is not a top "light return" performer right?
So not a surprise that it has some leakage under the table?

As designed by Garry, HCA's specifications for use: under 2 = worth further consideration.
That's *all* it says definitively. So by HCA's standards that stone is "worth further consideration". We consider further, and we see the problems that numbers and blunt weeding tools may conceal.

 

[babydoll_mini]

No I am referring to the thread I linked, read the q about halfway down the page - it asks exactly the same thing as your thread title.

That stone scores 'fine' on the HCA - under 2. In any case, don't try to select using the HCA - it's not designed as a selection aid.

Yeah, sorry, I just realized I have paste the wrong url. I've edited my reply.
But actually the HCA has anticipated that it is not a top "light return" performer right?
So not a surprise that it has some leakage under the table?

As designed by Garry, HCA's specifications for use: under 2 = worth further consideration.
That's *all* it says definitively. So by HCA's standards that stone is "worth further consideration". We consider further, and we see the problems that numbers and blunt weeding tools may conceal.

Yeah, you are right, that a stones scores below 2 may still have its problem.But I'm not arguing that "HCA < 2 <==> Ideal performance".

I'm saying that this HCA result has already implied the problem (the "very good" light return grade rather than "excellent") to us. That is a piece of information we can get without looking at any pic/IS/ASET, right? If I am the blind buyer, I will bypass this stone because of this.

And why does the thread hold number have to be 2.0, why not 2.1 or 1.9? If I make my own tighter thread hold say 1.0, can I go ahead and buying blindly without making mistakes?

 

[stone-cold11]

Because you are basing a grade off 4 numbers, 3 of which are average from 8 different measurements and then rounded. That is quite a variation. Add to the fact that these measurements only accounts for 17 of the 57 facets and takes no account of the orientation, skewness of the facets. If you want to buy it with that level of confidence, then it is up to you.

 

[babydoll_mini]

Because you are basing a grade off 4 numbers, 3 of which are average from 8 different measurements and then rounded. That is quite a variation. Add to the fact that these measurements only accounts for 17 of the 57 facets and takes no account of the orientation, skewness of the facets. If you want to buy it with that level of confidence, then it is up to you.

Stone-cold11, thank you for your reply! I think I understand what you are saying.
I'm not trying to justify blind buying you know. I'm not an advocator nor protester of blind buying at the moment, just trying to learn as much as possible.

I would love to know whether if there is a condition that blind buying can actually work.

As the factors you mentioned as orientation and skewness which is not covered in stats, I think the symmetry grade has some kind of assessment on those. So if the diamond is not so large, say less than 1 carat, how much visual difference can be caused by these unrevealed factors?

 

[babydoll_mini]

I also read this in the description of HCA:

"Stones near the center of the red region, those with the lowest scores, are often the least affected by small symmetry variations."

Does it mean, if a stone scores say 0.5, the chance that it can go wrong is so small that we can go for it without looking at the picture?

 

[Stephan]

I would not say that.
If you take a diamond with a 40.6 rounded pavilion and a 34 crown for example, if there are some symmetry variations (or some very light painting), you could have a diamond with too much obstruction.
The safest blind buys in my opinion are GIA triple EX with 34.5-34/40.8 or 33.5-33/41, 53-57 tables 55-60 stars and 75-80 LGF.
With more information like Idealscope etc., I'm much more open to other proportions, deeper or shallower.
I would not buy a diamond with 40.6 pavilion without IdealScope/ASET picture.

 

[Stephan]

Another blind buy possibility is a diamond that comes with a AGS Platinum DQD.
That's how I've bought my BlueNile diamond:
http://www.agslab.com/pdf_sync_reports/104047871002-PLDQR.PDF

 

[anitabee]

my question is, what is blue nile's return policy?

if it's reasonable then what's the harm in ordering from them?

 

[slg47]

my understanding is that they have a good return policy. the harm? well, depends...you're out shipping charges and maybe appraiser fees if you take it to an appraiser?

 

[Frenchcut]

I don't mean to "threadjack" but I have an additional question on the same theme, although it's not about buying "blindly": has anyone on this forum ever been disappointed by a H&A diamond purchased on the net?

I've spent a lot of time training my eyes on reports, ASET, Idealscope...and it will soon be time to choose my diamond. Still, I'm afraid something could go wrong, even when a picture of the actual diamond is available!

Am I being overcautious?!

PS: I know the return policy on WF, GOG...make it easier to pick a diamond as it can be sent back in case I'm disappointed but I don't live in the US so it makes things a bit more complicated for me...

 

[whatmeworry]

I also read this in the description of HCA:

"Stones near the center of the red region, those with the lowest scores, are often the least affected by small symmetry variations."

Does it mean, if a stone scores say 0.5, the chance that it can go wrong is so small that we can go for it without looking at the picture?

I won't say wrong, but I will say that your individual taste may prefer a diamond that scores over 2 than one that scores 0.5.

With round diamonds, I actually buy blind these days. With the use of noncontact scanners in grading and the greater precision of cutting these days, I'd buy GIA or AGS graded diamonds blind.

 

[babydoll_mini]

I would not say that.
If you take a diamond with a 40.6 rounded pavilion and a 34 crown for example, if there are some symmetry variations (or some very light painting), you could have a diamond with too much obstruction.
The safest blind buys in my opinion are GIA triple EX with 34.5-34/40.8 or 33.5-33/41, 53-57 tables 55-60 stars and 75-80 LGF.
With more information like Idealscope etc., I'm much more open to other proportions, deeper or shallower.
I would not buy a diamond with 40.6 pavilion without IdealScope/ASET picture.

Thank you QueenMum for your reply. You mentioned some black spot that I definitely need to learn more about.

Do you mean a combination of 40.6 pavilion and 34 crown, if rounded up from the wrong direction, might end up with a stone too shallow? And too shallow --> too much obstruction?

What puzzled me is that the conclusion above (I might understand you wrongly and made the wrong conclusion) is contradict with HCA scores. Such combination scores extremely high with HCA; does it mean such a combination can suffer least from small symmetry variations?

 

[babydoll_mini]

my question is, what is blue nile's return policy?

if it's reasonable then what's the harm in ordering from them?

I don't live in the US, so returning can be painful...

 

[babydoll_mini]

I also read this in the description of HCA:

"Stones near the center of the red region, those with the lowest scores, are often the least affected by small symmetry variations."

Does it mean, if a stone scores say 0.5, the chance that it can go wrong is so small that we can go for it without looking at the picture?

I won't say wrong, but I will say that your individual taste may prefer a diamond that scores over 2 than one that scores 0.5.

With round diamonds, I actually buy blind these days. With the use of noncontact scanners in grading and the greater precision of cutting these days, I'd buy GIA or AGS graded diamonds blind.

Eh, what is the noncontact scanners if you don't mind me asking?
Thank you!

 

[slg47]

I would not say that.
If you take a diamond with a 40.6 rounded pavilion and a 34 crown for example, if there are some symmetry variations (or some very light painting), you could have a diamond with too much obstruction.
The safest blind buys in my opinion are GIA triple EX with 34.5-34/40.8 or 33.5-33/41, 53-57 tables 55-60 stars and 75-80 LGF.
With more information like Idealscope etc., I'm much more open to other proportions, deeper or shallower.
I would not buy a diamond with 40.6 pavilion without IdealScope/ASET picture.

Thank you QueenMum for your reply. You mentioned some black spot that I definitely need to learn more about.

Do you mean a combination of 40.6 pavilion and 34 crown, if rounded up from the wrong direction, might end up with a stone too shallow? And too shallow --> too much obstruction?

What puzzled me is that the conclusion above (I might understand you wrongly and made the wrong conclusion) is contradict with HCA scores. Such combination scores extremely high with HCA; does it mean such a combination can suffer least from small symmetry variations?

HCA is a blunt weeding tool, only takes into account 4 averaged and rounded, there can be stones with obstruction that score fine on HCA.

 

[whatmeworry]

A Sarin machine is an example of a noncontact scanner. You might see the term "Sarin report". The scanner takes all sorts of measurements of the diamond, including the various angles. It can also be used to get an idea of how symmetrical the diamond is. So now that the labs are using them, it's hard for let's say a diamond with Ideal or Excellent symmetry to really have a wide variance in measurements. At least I've never seen one. I've seen lots of posters call in stones blind and then post the Sarin results and the measurements are usually in a tight range.

Anyway back to calling in a stone blind. By all means use the HCA as a guide but also check to see if it scores (the little "x") in the middle of GIA Excellent and AGS Ideal boxes. That would be a much "safer" pick if you were calling in blind. Also if you are really sharp eyed, you might want to stick to higher clarity diamonds.

 

[babydoll_mini]

A Sarin machine is an example of a noncontact scanner. You might see the term "Sarin report". The scanner takes all sorts of measurements of the diamond, including the various angles. It can also be used to get an idea of how symmetrical the diamond is. So now that the labs are using them, it's hard for let's say a diamond with Ideal or Excellent symmetry to really have a wide variance in measurements. At least I've never seen one. I've seen lots of posters call in stones blind and then post the Sarin results and the measurements are usually in a tight range.

Anyway back to calling in a stone blind. By all means use the HCA as a guide but also check to see if it scores (the little "x") in the middle of GIA Excellent and AGS Ideal boxes. That would be a much "safer" pick if you were calling in blind. Also if you are really sharp eyed, you might want to stick to higher clarity diamonds.

Thank you whatmeworry! This is so very informative~!

I was actually wondering the meaning of the "x" and the white boxes.
The one with solid while outline is GIA Ex and AGS ideal box and the one with dotted line is for HCA, am I right?
A 34/40.6 combination may have very low score but the "x" is quite at the boundary of the white box. It kind of explains...

And about the Sarin machine, is it something one can have at home? I guess not. Or one can ask the vendor for the number? For example, will BlueNile provide it if I ask?
Thank you very much again!

 

[whatmeworry]

Almost. If you're inside the solid white box, then it's possibly an AGS-0. If you're inside the dotted white box, then it's possibly a GIA Excellent. BlueNile will probably tell you that they can't or won't run a Sarin. But I remember one poster who persisted and got it done. He basically told BlueNile to get him a Sarin or they had no sale.