Crown and Pavilion angles on Certs?

[hunter3316]

I want to use the cut advisor on this site to buy the best diamond for the $$$ however I am finding that none of the certs contain the necessary informaiton such as Crown and Pavilion angles. The certs always have Table and depth %''s but I need the other two angles as well. Am I missing somthing here??? are there some certs that have these needed angles? Can my jewler measure these for me on? If so that seems pritty laborious... I could see my jewler getting pritty pissed off if I asked him to go thourh 2 dozen diamonds giving me all the #s I need. Any help would certainly be appreciated?

 

[optimized]

Hi Hunter,

You've certainly hit upon a major gripe of the educated diamond shopper. Indeed, many a diamond is for sale without some of the information that would be helpful in determining the mathematical optical performance of the cut, but there are some options available to the determined consumer.

First of all, while GIA reports don't include the relevant angles, AGS reports do contain average crown and pavilion angles so perhaps that will help you. I think it will be only a matter of time until GIA starts including more of this information on their certs (they already do the Sarin analysis for the stones they grade), but in the meantime AGS enjoys an advantage in this regard. Both GIA and AGS certs are extremely respected within the industry so either should be reliable for you.

Another thing you can look for is detailed Sarin or Megascope analyses for stones you are considering. Many online vendors include these reports with the stones they list and an increasing number of bricks and mortar dealers are starting to see the benefits as well. These reports will give you all the information you need.

Most jewelers are ill-equipped to provide this information, but some will be willing to obtain the reports for you on specific stones they offer. They won't want to send a boatload of stones out to be scanned, but if you have a specific stone that you really like some jewelers will have the diamond scanned for you if that's what it takes to make the sale.

-Tim

 

[hunter3316]

Thanks for the advise optimized, that will certainly help things out. Howevr I still have one more question. It seems to me that good crown and pavilian angles have a pritty small talerence wereas the table and depth %'s can change quite a bit while still maintaining a great diamond (HIC). So my question is how often would one find a diamond with a crown or pavilian angles that fell outside of the 34.3-34.7 (crown) and 40.0-40.9 (pavilian) tolerences. In other words If i bought say a 57 table 60 depth diamond how likeely would it be that the crown and pavilian angles are going to be outside of the above tolerences?

Thanks for you input, this forum is great!

 

[optimized]

):

The image shown is of two stones that both have 60% depth and 60% table measurements (a combination of proportions that is sometimes erroneously promoted as "safe"). As you can see, it's quite possible for the basic specifications of a diamond to be similar while the angles are extremely different. Going by depth/table percentages alone will yield decidedly unpredictable results. I wish it were that easy, but alas, it just isn't so...

-Tim

[/u]

 

[niceice]

To expand on the 60/60 concept, a diamond with a 60/60 total depth and table ratio could have a proportions rating of AGS-2 Very Good or AGS-10 Very Poor... Get the Sarin or OGI proportions information, don't rely on the possibility of averages... And when you do get the proportions report, make sure that you get the full report that provides the high and low points that comprise the average measurements... The simple label is not enough! Get the full page report that is available from the Sarin / OGI machines and you'll really have the information necessary to make an educated choice!