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Well I just bought a pair of OECs

AV_

Ideal_Rock
Joined
Aug 5, 2018
Messages
3,367
"Too much" is what I'm aiming for!
It is!

I sort of remember that the ring with pears & two marquises adds up to about five carats; truth be told, I have no idea if a version with rounds makes sense.
 

dreamer_dachsie

Super_Ideal_Rock
Joined
Dec 16, 2007
Messages
24,360
Well I like where you are headed and BIG and BOLD seems the way to go.
 

distracts

Ideal_Rock
Premium
Joined
Oct 11, 2011
Messages
5,495
Ok I picked up the diamonds today from Southwest Diamond Cutters - the one that was the “problem” one looks SO GOOD! The only way I can tell them apart now is that the one that didn’t get recut is more off-round and has chips, but I can’t tell just by looking at the way they sparkle.

The one that was recut went from 1.21 to 1.17. The other is 1.14. Both around 6.5mm with some variance because they’re not super round.

Unaltered on top, recut below:

064367D3-FD04-4A84-A549-8E377974A816.jpeg
6ED6B728-B031-4A7A-BCA4-18DE4224E61D.jpeg

I know the differences before were subtle but they would have driven me crazy if they were set together and now I’m entirely pleased with the pair.
 

distracts

Ideal_Rock
Premium
Joined
Oct 11, 2011
Messages
5,495
(For anyone who doesn't want to backread - the bottom stone under the table turned all off or all on - and only rarely the latter - it didn't, like, scintillate. Which it now does.)

ALSO that stuff that I thought was inclusions and everyone else thought was dirt but I could not for the life of me clean off? Gone. It was dirt. It just needed a much, much more serious cleaning than I was giving it.

Also here are the other numbers, for anyone curious, since we don't talk about OEC numbers much (hi @sledge this may be of interest to you!) :

Stone 1 (unaltered):
ct 1.14
Diameter 6.54mm
Depth 65.48%
Crown Height: 18.45%
Pav Depth: 43.89%
Culet size: 4.96%
Table size: 44.1%
Crown angle: 32.83
Pav angle: 43.09
Star length: 42.8%
Lower halves: 55.2%
Girdle Thickness: 2.98%
Girdle min-max: Extremely thin to very thin

Stone 2 (original):
ct 1.21
Diameter 6.6mm
Depth 65.88%
Crown Height: 17.98%
Pav Depth: 43.19%
Culet size: 9.98%
Table size: 48.3%
Crown angle: 35.13
Pav angle: 44.01
Star length: 40.2%
Lower halves: 51.5%
Girdle Thickness: 4.30%
Girdle min-max: Extremely thin to very thin

Stone 2 (post recut):
ct 1.17
Culet size: very large
Table size: 45%
Crown angle: 33
Pav angle: 44
Star length: 40%
Lower halves: 50%
Girdle Thickness: 5.5%

Compare to the stats of the AVR I bought the other week:
ct 0.745
Diameter: 5.7mm
Depth 65.3%
Crown Height: 18%
Pav Depth: 44.1%
Culet: pointed
Table size: 49.2%
Crown angle: 35.3
Pav angle: 41.4
Girdle min-max: thin to slightly thick

It has me interested in the proportions of my other OECs - I suspect they're mostly pretty close to the first one because I definitely have a look I like.
 

prs

Brilliant_Rock
Premium
Joined
Dec 26, 2017
Messages
1,001
Also here are the other numbers, for anyone curious, since we don't talk about OEC numbers much (hi @sledge this may be of interest to you!) :

It has me interested in the proportions of my other OECs - I suspect they're mostly pretty close to the first one because I definitely have a look I like.
Great work! I'm thinking the tweak was to lower the crown angle from 35.1° to 33.0° thus decreasing the table from 48.3 to 45%.

It's such a shame that GIA only provides the numbers for table and total depth for the stones they call "Old European Brilliant". I wonder what their criteria are for diamonds to qualify for this cut name? I would think it has to include other numbers, including star and lower girdle lengths. Otherwise there would be no chunky facets; the calling card of a good OEC.

If anyone knows what those criteria are, I would be delighted to learn more.
 

prs

Brilliant_Rock
Premium
Joined
Dec 26, 2017
Messages
1,001
Thank you! I think both @distracts diamonds would meet the GIA criteria for "Old European" and "Circular". It seems strange they include a star length requirement for "Circular" but not for "Old European". Does the star facet length impact how "chunky" the crown facets look?
 

PreRaphaelite

Brilliant_Rock
Joined
Feb 2, 2015
Messages
1,901
Interesting - by this chart, the AVRs with pointed culets don't meet GIA's definition of OECs.
That might be part of @Rhino ’s logic in maximizing performance but working collaboratively with GIA to differentiate the proprietary cut of AV from stones cut in olden days. My understanding from watching the lecture video where the issue was discussed, was that each camp was very respectful in considering each other’s perspectives.

 

Rhino

Ideal_Rock
Trade
Joined
Mar 28, 2001
Messages
6,271
That might be part of @Rhino ’s logic in maximizing performance but working collaboratively with GIA to differentiate the proprietary cut of AV from stones cut in olden days. My understanding from watching the lecture video where the issue was discussed, was that each camp was very respectful in considering each other’s perspectives.

Actually there are 2 out of the 4 that would disqualify the AVR from being an Old European cut according to GIA's definition. The crown angles are less than 40 degrees as well as the culet.
 

prs

Brilliant_Rock
Premium
Joined
Dec 26, 2017
Messages
1,001
That might be part of @Rhino ’s logic in maximizing performance but working collaboratively with GIA to differentiate the proprietary cut of AV from stones cut in olden days. My understanding from watching the lecture video where the issue was discussed, was that each camp was very respectful in considering each other’s perspectives.

Thank you so much for posting this. I guess the most useful thing I learned from the video is the lower girdle facets are the most important factor in determining an OEC, or an OEC style stone.

This point only came up towards the end, thanks to @Rhino, and there seemed to be unanimous agreement. It sure would be nice to know if the most beautiful OECs tended to have 65%, 60%, or <60% LGFs.
 
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