coda72
Brilliant_Rock
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Is there a Radiant Cut Advisor?
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fancyrock
Brilliant_Rock
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Thanks, coda72 !!!
I had the same trouble with the direct sunlight. I read the same thing on here to explain why that happens to the best well-cut diamonds (round and fancy). I had no choice but to accept it and move on. My stone has not black/gray areas. I blinded my husband whenever he was driving!! It sparkles like mad.
As much as I got laughed at by some jewelers... I was determine to find a nice rock with table/depth around 65%. When I spotted this baby on James Allen''s site... I hurried over to David Atlas'' site and check for its grading. Sure enough... it''s... it''s... it''s... 1A.
1.94 ct Radiant (sorry, but I can''t recall the mm measurements)
Table - 64%
Depth - 65%
diamondsbylauren
Brilliant_Rock
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OK- I've had a long talk with Stan, and we've agreed.
From now on we'll toss ALL our knowledge and experience in the trash bin, and start buying our diamonds based on a cut grade table and a sarin report. I really appreciate the help here- I mean it's just such a pain to actually look at a diamond.
Now we can skip all those nasty non 1A's!!!!
Firerock- It's absolutley fantastic you love your diamond- but by sticking to a chart, you very well may have missed some awesome stones
From now on we'll toss ALL our knowledge and experience in the trash bin, and start buying our diamonds based on a cut grade table and a sarin report. I really appreciate the help here- I mean it's just such a pain to actually look at a diamond.
Now we can skip all those nasty non 1A's!!!!
Firerock- It's absolutley fantastic you love your diamond- but by sticking to a chart, you very well may have missed some awesome stones
Shay37
Ideal_Rock
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diamondsbylauren
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Discrepencies between Sarin ( OGI) and GIA are the norm.
When you''re measureing somethign so small, the tolernces are going to mean that variation between the measuring tool, as well as things like how the diamond is placed in the Sarin will affect the results.
I''d say that the question I''d have is price.
$3350pc seems unreasonably low in today''s market for a desirable, well cut one carat F/SI1 Radiant cut with GIA.
If it''s there and that''s the price, that would be amazing.
But I''ve yet to see a reputable dealer selling desirable diamonds well below market value.
When you''re measureing somethign so small, the tolernces are going to mean that variation between the measuring tool, as well as things like how the diamond is placed in the Sarin will affect the results.
I''d say that the question I''d have is price.
$3350pc seems unreasonably low in today''s market for a desirable, well cut one carat F/SI1 Radiant cut with GIA.
If it''s there and that''s the price, that would be amazing.
But I''ve yet to see a reputable dealer selling desirable diamonds well below market value.
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The scanner discrepency is huge problem.
gia wrote this Why are different measurements reported for the same diamond samples in the Fall 2001 and Fall 2004 Gems & Gemology articles?
Quoting the Fall 2004 Gems & Gemology article (p. 206): “Research Diamonds RD01-RD27 and RD 29 were previously reported in Reinitz et al. (2001); variations in proportion values from that article are the result of recutting, measuring device tolerances, and/or the application of rounding.” Since the 2001 article, we have been able to reexamine and refine our measuring practices based on advancements in measurement technology. In the most recent paper, the measurements we report have been rounded in a manner consistent with the standards of our grading system. As explained below, we believe that the new measurement values represent an appropriate precision given the ability of observers to consistently discern differences in appearance and of manufacturers to reproduce the specific proportions.
[ top ]
In some cases (e.g., table size or pavilion angle), our reported measurements are the tightest that are practical, given how reproducible those measurements are on the same or a similar, properly calibrated, measuring device. In addition, we carefully considered the level of precision that would be sufficient for our system without over-burdening cutters. We then conducted experiments with actual diamonds to check and support this level of precision. By not demanding more precision than visual discernment supports, we feel we have reached the best practical, reproducible solution for consistent cutting and reporting.
[ top ]
http://www.gia.edu/research/29324/diamond_cut_faq.cfm#measurments1 at this link.
They are using rounded data to 0.5 degrees on Crown angles - this is a huge statement against the accuracy of scanners out there.
Round diamonds are comparitively easy for scanners to measure because they always have the same # of facets in the same places (more or less).
So when you come to things like radiants or other fancy cuts - the information from the scans can be useless in the sense that many facets are simply not recorded picked up - this means that stones with many variations of facet structure get very poor scan accuracy..
One way around this is to build better scanners - but humans say - we want convenience I want to buy 1 machine that scans 2mm to 30mm diamonds - well - Sarin and Ogi solve that problem by making scanners with interchangeable lenses so that there are lenses for 2-8mm and 6 to 15mm and 12 to 30mm for example - but making the lenses line up perfectly each time introduces new errors.
The Helium scanner has a fixed lens system that is higher quality optics and much more accurate. You loose this convenience factor - which is OK for a lab - they can have 1 scanner for each size because they need several anyway.
But for all the businesses that already own an old less accurate scanner - well they do not like the idea of 2 or 3 new Helium scanners at 15k each.
Summary - as you are being told - there is not a lot of value knowing this data anyway - and the data is not very accurate as you found out.
If you are going to use scan ifo - then try to get real 3D scans and look at the stone the next best thing to in the real world using OctoNus Gem Adviser. then you can do Ideal-scope and ASET anaylsis and other more useful stuff.
Otherwise - you need to see the stones, or trust someone - and like you, I am lothe to trust people.
Finally - some people tell you to look at photo''s - well - guess what - cameras can be taught to lie too.
gia wrote this Why are different measurements reported for the same diamond samples in the Fall 2001 and Fall 2004 Gems & Gemology articles?
Quoting the Fall 2004 Gems & Gemology article (p. 206): “Research Diamonds RD01-RD27 and RD 29 were previously reported in Reinitz et al. (2001); variations in proportion values from that article are the result of recutting, measuring device tolerances, and/or the application of rounding.” Since the 2001 article, we have been able to reexamine and refine our measuring practices based on advancements in measurement technology. In the most recent paper, the measurements we report have been rounded in a manner consistent with the standards of our grading system. As explained below, we believe that the new measurement values represent an appropriate precision given the ability of observers to consistently discern differences in appearance and of manufacturers to reproduce the specific proportions.
[ top ]
Why doesn’t GIA report measurements to greater precision?
There are three main aspects to this issue: how much precision is needed for our cut system (as indicated by the observation results), how much precision is practical for cutters to achieve, and the reproducibility of measurements (rather than the precision of any single measuring instrument). Although we could report measurements to a finer scale, we determined—based on the reproducible distinctions made by human observers—that such a high level of precision was not warranted. To check this, we examined each proportion parameter at two or more levels of precision to explore the differences in calculated metric values and the ultimate grade. Our results demonstrated that very subtle changes in measurements seldom altered a final prediction, or human assessment, of overall appearance; there was no need to demand tighter tolerances at this point.
In some cases (e.g., table size or pavilion angle), our reported measurements are the tightest that are practical, given how reproducible those measurements are on the same or a similar, properly calibrated, measuring device. In addition, we carefully considered the level of precision that would be sufficient for our system without over-burdening cutters. We then conducted experiments with actual diamonds to check and support this level of precision. By not demanding more precision than visual discernment supports, we feel we have reached the best practical, reproducible solution for consistent cutting and reporting.
[ top ]
http://www.gia.edu/research/29324/diamond_cut_faq.cfm#measurments1 at this link.
They are using rounded data to 0.5 degrees on Crown angles - this is a huge statement against the accuracy of scanners out there.
Round diamonds are comparitively easy for scanners to measure because they always have the same # of facets in the same places (more or less).
So when you come to things like radiants or other fancy cuts - the information from the scans can be useless in the sense that many facets are simply not recorded picked up - this means that stones with many variations of facet structure get very poor scan accuracy..
One way around this is to build better scanners - but humans say - we want convenience I want to buy 1 machine that scans 2mm to 30mm diamonds - well - Sarin and Ogi solve that problem by making scanners with interchangeable lenses so that there are lenses for 2-8mm and 6 to 15mm and 12 to 30mm for example - but making the lenses line up perfectly each time introduces new errors.
The Helium scanner has a fixed lens system that is higher quality optics and much more accurate. You loose this convenience factor - which is OK for a lab - they can have 1 scanner for each size because they need several anyway.
But for all the businesses that already own an old less accurate scanner - well they do not like the idea of 2 or 3 new Helium scanners at 15k each.
Summary - as you are being told - there is not a lot of value knowing this data anyway - and the data is not very accurate as you found out.
If you are going to use scan ifo - then try to get real 3D scans and look at the stone the next best thing to in the real world using OctoNus Gem Adviser. then you can do Ideal-scope and ASET anaylsis and other more useful stuff.
Otherwise - you need to see the stones, or trust someone - and like you, I am lothe to trust people.
Finally - some people tell you to look at photo''s - well - guess what - cameras can be taught to lie too.
diamondsbylauren
Brilliant_Rock
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Hi Garry- I don't know if Happy Thanksgiving is appropriate- but my best wishes in the holiday season to you and yours.
Yes, cameras can certainly lie- or simply show a side which is most complimentary. Just like people, diamonds look better in some photos than others.
So, an honest seller would use the best looking photos of the diamonds, that makes sense.
Then you might find dishonest sellers who manipulate photos.
Same thing with measurements. A less than ethical seller can use stats to imply things which are not in evidence.
But again- an honest, knowledgable seller will be able to separate the wheat from the chaff, as it were.
What difference does it make if calibrations on machines measuring tolerances we can't see are not agreeing? Well what difference if people are honest.
Why build scanners that can measure every angle of every facet when we already know how to cut diamonds that people love. To me it's kind of like trying to figure out how many angels fit on the head of a pin.
Diamonds- and the cutting of diamonds- is an art. The cutter must use the natural substance- a very expensive and rare material- to craft the best possible finsihed product.
There's already machines which can guide the cutter - making a "Road Map" for them to acheive whatever cut they are going for.
Yet the practicalities of this remarkable material neccesitate human decsison making along the way.
So it's a meld of man's ( or woman's) hand- and technology that assists cutters in their art.
Now, we are discussing how to quantify what these cutters produce.
At this point, I feel it's more productive to take a more broad overveiw of the polished diamond.
I really don't need to know if it's 62, or 64% table to determine ifit's a desirable, well cut radiant. Neither does the person buying it.
After looking at just a few diamonds, a "laymen" can easily spot a badly cut diamond. They won't be an expert- and should certainly pay alot of attention to who they are buying from- but they will know what they like.
Yes, cameras can certainly lie- or simply show a side which is most complimentary. Just like people, diamonds look better in some photos than others.
So, an honest seller would use the best looking photos of the diamonds, that makes sense.
Then you might find dishonest sellers who manipulate photos.
Same thing with measurements. A less than ethical seller can use stats to imply things which are not in evidence.
But again- an honest, knowledgable seller will be able to separate the wheat from the chaff, as it were.
What difference does it make if calibrations on machines measuring tolerances we can't see are not agreeing? Well what difference if people are honest.
Why build scanners that can measure every angle of every facet when we already know how to cut diamonds that people love. To me it's kind of like trying to figure out how many angels fit on the head of a pin.
Diamonds- and the cutting of diamonds- is an art. The cutter must use the natural substance- a very expensive and rare material- to craft the best possible finsihed product.
There's already machines which can guide the cutter - making a "Road Map" for them to acheive whatever cut they are going for.
Yet the practicalities of this remarkable material neccesitate human decsison making along the way.
So it's a meld of man's ( or woman's) hand- and technology that assists cutters in their art.
Now, we are discussing how to quantify what these cutters produce.
At this point, I feel it's more productive to take a more broad overveiw of the polished diamond.
I really don't need to know if it's 62, or 64% table to determine ifit's a desirable, well cut radiant. Neither does the person buying it.
After looking at just a few diamonds, a "laymen" can easily spot a badly cut diamond. They won't be an expert- and should certainly pay alot of attention to who they are buying from- but they will know what they like.
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Happy Thanksgiving to you and all the other Americans who celebrate it David.
I celebrate the discoveries of Chris C - tomatoes and chilli pepper. Where would we be without them?
Re the tools for cut grading and the art of diamond cutting.
This stone here is an example of the science of diamond cutting.
http://com.pricescope.com/photos/stones/picture613.aspx
Here is the rough stone http://com.pricescope.com/photos/stones/picture614.aspx
Without clear rules as to what proportioned diamond to fit within the spaces between inclusions it is unlikely any artisan could have ever achieved the return and yeild that the Helium Rough scanner guided the cutter who owned this stone.
The rules for the proportions did not just happen.
And the benefit to everyone from this science is is measurable - you may know that average historic yeilds have risen from around 30% or less, to over 40% in many factories equipped with modern scanner technology David.
That is one of the main reasons why many smaller sized diamonds are available today at the same price as they were many years ago.
Some of the decisions cutters make actually come from the implimentation of tools that have been implimented into scanners from people who contribute and learn collectively on this board, like the inventor of the OCtoNus Helium scanner, Serg Sivovolenko.
I celebrate the discoveries of Chris C - tomatoes and chilli pepper. Where would we be without them?
Re the tools for cut grading and the art of diamond cutting.
This stone here is an example of the science of diamond cutting.
http://com.pricescope.com/photos/stones/picture613.aspx
Here is the rough stone http://com.pricescope.com/photos/stones/picture614.aspx
Without clear rules as to what proportioned diamond to fit within the spaces between inclusions it is unlikely any artisan could have ever achieved the return and yeild that the Helium Rough scanner guided the cutter who owned this stone.
The rules for the proportions did not just happen.
And the benefit to everyone from this science is is measurable - you may know that average historic yeilds have risen from around 30% or less, to over 40% in many factories equipped with modern scanner technology David.
That is one of the main reasons why many smaller sized diamonds are available today at the same price as they were many years ago.
Some of the decisions cutters make actually come from the implimentation of tools that have been implimented into scanners from people who contribute and learn collectively on this board, like the inventor of the OCtoNus Helium scanner, Serg Sivovolenko.
diamondsbylauren
Brilliant_Rock
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Not yet David.
There is little demand for this type of eqiuipment in USA.
It is one of the reasons USA is shrinking as a manufacturing unit.
Helium began life as Pacor in Belguim, and almost all the helium units are in India, which btw is Sarin''s far greater market (about 20 times bigger than USA I think).
There is little demand for this type of eqiuipment in USA.
It is one of the reasons USA is shrinking as a manufacturing unit.
Helium began life as Pacor in Belguim, and almost all the helium units are in India, which btw is Sarin''s far greater market (about 20 times bigger than USA I think).
diamondsbylauren
Brilliant_Rock
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Well, this might not be what you''re talking about Garry, but I do know we have a OGI machine which works with a comuter to assist the cutters in visualizing what they are doing.
Here''s a photo of a partially finished radiant cut, with the outline of the finished stone drawn in by the computer.
diamondsbylauren
Brilliant_Rock
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I would NOT rule out the good old ol' US of A just yet my friend.
There's a LOT of diamond cutting going on in the USA- primarily larger more important stones. There's also quite a bit of jewelry manufacturing done here.
Diamonds cut in America, by Americans for Americans, and the rest of the world. There's quite a bit of jewelry manufactured in the US heading east over the Atlantic to Europe these days.
Some of the world's best diamonds are cut here, and the best jewelry manufactured here.
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Ogi is the market follower in this field David.
The innovation leader is OctoNus with its Helium scanner that accounts for inclusions in rough planning, and has the most accrate scan models and indentation detection systems.
Sarin is the market leader by virtue of incumbent position; OctoNus has only recently began to scale up its operations.
Remeber that most of the North American planning equipment is going to Canada.
And even Tiffany is setting up its manufacturing units in India.
There is no doubt that USA is a leading manufacturer of large diamonds David. But this position is not one of growth. The reason I think you will find is that India (which began because of cheap labour) has embrassed new technology.
The next developments will come in Africa as companies like Lev Lieve build factories in diamond mining countries.
This is Sarins geo market share:
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diamondsbylauren
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Hey Steve,
Congratulations!
You seem to have found a seller offering dollar bills for 80 cents.
Kind of like someone offering brand new BMW cars for $20k.
A desirable, well cut 1.01 F/SI1 Radiant diamond with GIA report costs dealers more than $3700 today. Of course it''s posssible that it''s not an eye clean SI1.
Please keep us updated on this. I''d love to know how it turns out!
PS- many times, a price to low indicates potential problems- some very serious.
Congratulations!
You seem to have found a seller offering dollar bills for 80 cents.
Kind of like someone offering brand new BMW cars for $20k.
A desirable, well cut 1.01 F/SI1 Radiant diamond with GIA report costs dealers more than $3700 today. Of course it''s posssible that it''s not an eye clean SI1.
Please keep us updated on this. I''d love to know how it turns out!
PS- many times, a price to low indicates potential problems- some very serious.
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diamondsbylauren
Brilliant_Rock
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Last time I remeber you made these dispersions many of the good prosumer folk on Pricescope found a multitude of stones that were better quality and less cost than your advice / prices David.
I have not looked at the prices of the said stone - but I know not to believe averything that you say is a fact.
I have not looked at the prices of the said stone - but I know not to believe averything that you say is a fact.
diamondsbylauren
Brilliant_Rock
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Garry- rather than sling around insults and accusations, wouldn''t it be more productive if you did actually take a look at the situatin at hand.
If I think someting is priced too low, and it actaully does turn out to be legit, I''ve only heloed another seller, right.
YOu do like to sling mud.
On the other hand I have been willing to put my name on the line and make specific pricing observatiions
If I think someting is priced too low, and it actaully does turn out to be legit, I''ve only heloed another seller, right.
YOu do like to sling mud.
On the other hand I have been willing to put my name on the line and make specific pricing observatiions
diamondsbylauren
Brilliant_Rock
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I do not like to sling mud David. But you do like to take a free ride on this board, while playing mum's the word on another when mud is being slung this way.
More importantly, I do not like to see people who blatantly come here to promote their products by instilling the fear factor with the sole intention of making a sale at other peoples expense. The expense is not so much other vendors - it is at the expense of consumer's peace of mind.
I see a very reputable Pricescope vendor (one who actually pays to promote his goods here on Pricescope and behave in a very gentleman like manner) is listing this diamond David.
Would you care to link us to the other thread where you were caught out frightening a consumer - I am sure you remember when and what is was about better than I do.
coda72
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Smh - on paper, that diamond seems great, but remember, not even the experts can judge a radiant on paper. It''s a "database" diamond, meaning that your vendor is just providing a listing from his vendor. When he gets the stone in, have him describe the SI and the life to you. Pay particular attention to whether there is a black circle around the culet. The only red flag that I can see from the numbers leads me to believe that this could (but may not) be a problem with the stone. Also, the price makes more sense if it''s a "lucky" SI1, so find out if it''s a "borderline" call. If it''s "borderline" it may still make sense to buy it, but you should know what you''re getting.
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Garry - this isn''t my fight, so I probably should not get involved, but your posts raise a couple of questions, so I''m interested in getting clarification.
1. What do you mean when you say that David is "getting a free ride." Is pricescope a consumer information site or a vehicle for directing business to vendors who pay for the privilege. I have been posting here in the belief that it was the former. If it is the latter, then I probably should stop posting since, while I have great respect for many pricescope vendors, I have no interest in directing business in any particular direction.
2. If I understand David''s post correctly, he''s saying that a low price can sometimes be a red flag that something may be wrong with the stone. If anything, the criticism of his post should be that his point is rhetorical - everyone knows that in life you get what you pay for. Sometimes you''re getting a real bargain, but sometimes things are cheap for a reason, and an educated consumer would want to know why.
pricescope
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Stan, posting here is a mutual benefit for both vendors and consumers as long as it stays educational and civil.
Vendors who offer useful advise without self promotions gather appreciation, recognition and quite a bit of business from the community. Using the forum, posting your name, company name and website in your signature is free and powerful promotion - it is indeed a "free ride" at the expense of advertisers.
In order to keep the integrity and quality of the environment we developed certain policies including "Do not create fear-based doubts in consumers' minds ".
Note, that the same rules apply to any forum member no matter whether it is an advertiser or not.
Even if David hasn't intended to score a sale, posting things like that for a vendor is a no-no on this forum. In several cases David used this "red flag" when the diamonds were perfectly fine, available, and consumers got them without any problems.
Instead of posting "price is too good to be true", it would be more appropriate to suggest to get a ball park price using the Pricescope search engine and if the price is too low to check verify the stone with independent appraiser.
The problem is that David has often breached this and other forum policies in the past and we have had to remind him about it privately and politely.
In many cases forum members have to step in when they see someone breaching the rules. That is why Garry had to remind David about the forum etiquette.
Hope this helps...
Vendors who offer useful advise without self promotions gather appreciation, recognition and quite a bit of business from the community. Using the forum, posting your name, company name and website in your signature is free and powerful promotion - it is indeed a "free ride" at the expense of advertisers.
In order to keep the integrity and quality of the environment we developed certain policies including "Do not create fear-based doubts in consumers' minds ".
Note, that the same rules apply to any forum member no matter whether it is an advertiser or not.
Even if David hasn't intended to score a sale, posting things like that for a vendor is a no-no on this forum. In several cases David used this "red flag" when the diamonds were perfectly fine, available, and consumers got them without any problems.
Instead of posting "price is too good to be true", it would be more appropriate to suggest to get a ball park price using the Pricescope search engine and if the price is too low to check verify the stone with independent appraiser.
The problem is that David has often breached this and other forum policies in the past and we have had to remind him about it privately and politely.
In many cases forum members have to step in when they see someone breaching the rules. That is why Garry had to remind David about the forum etiquette.
Hope this helps...
Thank you Stan!
Could you claify this "Also, the price makes more sense if it''s a "lucky" SI1, so find out if it''s a "borderline" call. If it''s "borderline" it may still make sense to buy it, but you should know what you''re getting."
Meaning the inclusion could be the reason for the price?
I have also found this one. Waiting for the megascope report.
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Past, Present, Future: The Meaning of Three-Stone Engagement Rings
Past, Present, Future: The Meaning of Three-Stone Engagement Rings - 04/14
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