Grading OECs

[Krisking]

Why are some OECs GIA-graded as "Round Brilliant" with "Fair/Good/etc." Cut Grade, while others are graded as "Old European Brilliant" (with no cut grade)?

Does these two certs have different appraisal and replacement implications?

 

[KKJohnson]

Following! This is a good question

 

[Karl_K]

https://www.gia.edu/gia-news-research-round-brilliant-cut-diamond-pay
quote:
In practice, if a diamond meets three out of the four criteria, it will still receive the old European cut designation on a GIA grading report.
GIA identifies classic old European cuts using these criteria:

• Table size: less than or equal to 53 percent
• Crown angle: greater than or equal to 40 degrees
• Lower half facet length: less than or equal to 60 percent
• Culet size: slightly large or larger
  

 

[Karl_K]

Same source.
Quote:
GIA decided to introduce a new description for 58-facet round brilliants. The requirements for a stone to fall into this new category are:

• Lower half length: less than or equal to 60 percent
• Star length: less than or equal to 50 percent
• Culet size: medium or larger

The new description used on GIA reports for these diamonds is “circular brilliant.” All three criteria must apply for the diamond to be designated as a circular brilliant

 

[Karl_K]

There are a ton of American cut vintage oec's that do not fit that criteria as American cutters moved towards the "ideal" cut proportions that are still in use today except with longer lgf%.

 

[Karl_K]

A must read for oec fans:
amazon:
https://www.amazon.com/American-Cut-First-100-Years/dp/0873110595
Free:
https://archive.org/details/AmericanCut--theFirst100YearsTheEvolutionOfTheAmericanCutDiamond

 

[Krisking]

Thank you, @Karl_K.

 

[rubybeth]

Why are some OECs GIA-graded as "Round Brilliant" with "Fair/Good/etc." Cut Grade, while others are graded as "Old European Brilliant" (with no cut grade)?

Does these two certs have different appraisal and replacement implications?

Yes, unfortunately, GIA certificates are problematic for those trying to insure older cuts that don't fit GIA's narrow parameters. I had a major problem with this for my OEC/transitional/whatever the heck you want to call it back when I tried to get an appraisal that accurately reflected the cut of the stone for replacement purposes. You can read my whole saga here: https://www.pricescope.com/communit...n-old-european-cut-insurance-question.214348/

 

[Krisking]

Thanks, @rubybeth! Your thread was also helpful. It sounds like a good appraiser, a trip to AGS, or both, are necessary.

 

[rubybeth]

Thanks, @rubybeth! Your thread was also helpful. It sounds like a good appraiser, a trip to AGS, or both, are necessary.

Yes, I wouldn't let a GIA report deter me from buying a stone that I loved, but I would use an appraiser who would accurate describe the stone and include images for replacement value purposes. Ultimately, I learned that I would probably not use that appraisal service again for old cuts--only modern cut diamonds. It was weird because I have an antique 5-stone ring which they accurately described as having OECs, so I was very surprised when they would only use GIA's language on the appraisal for the solitaire. I didn't want to pay for another appraisal, and it was more cost effective to get the AGS certificate (and Erica made the ring more beautiful with the reset anyway).