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Over Excellent Diamonds

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mdx

Brilliant_Rock
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Mar 1, 2002
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Does anyone have any details or specs on the Japanese OE and OE2 cuts and in particular the princess style?
Regards
Wayne
 
Does anyone want to explain what the heck over-excellent diamonds are?
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R/A <---- too lazy to google!
 
Next time I'm talking to my boss about getting a raise I'm going to describe myself as "over excellent".
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Rich and R/A

The over excellent is mentioned in the March 7th issue of Rapaport diamond report under the heading Japan Market Report page 80

Basically the manufacturer Hohoemi Brains Inc. claims to have produced a cut far superior in terms of brilliance than the cuts we know.

If you cant find it and have some interest. I,ll type it out and post it.( Hate typing though)

Wayne
 
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Basically the manufacturer Hohoemi Brains Inc. claims to have produced a cut far superior in terms of brilliance than the cuts we know.
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Yeah, and if I had a dollar for every time I've heard that claim attached to a new cut design or new branded diamond, I could retire tomorrow.
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I'd be interested in more information myself.
 
Ok, I found the company website...but it's not in English. They do have some pictures on there though if you want to check it out.

http://www.hohoemi.co.jp/O_E_cut.htm
 
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Resurrecting this dead thread to add that I believe these are based on the Okuda cut. At least the patents cite Okuda and many of the ideas central to these (crown-to-crown rays, table-to-crown rays, calculated focal lengths, color enhancement through optimization of blue/purple fire, etc.) seem also to be present in the Okuda patent. These seem to have very odd proportions. I tried to run some numbers on the HCA but it wouldn''t allow the table sizes and pavilion angles.
 
Date: 1/27/2005 17:29 AM
Author: Superidealist
Resurrecting this dead thread to add that I believe these are based on the Okuda cut
...I tried to run some numbers on the HCA but it wouldn''t allow the table sizes and pavilion angles.
So... what are these numbers ?
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I don't remember all of them but I do recall one with a 38% table. I believe another had a crown angle of around 28 degrees. In general, they had shallow pavilion and crown angles and small tables. The HCA warned of fisheye on the one that I think it did take. From the patent illustrations it looked like there might be significant leakage under the table. I'll post more when I have time.
 
The US patent numbers for the O.E. round and the O.E. princess are 6694778 and 6818280 respectively. The Okuda cut is the second foreign patent cited in the O.E. round patent application. The Okuda cut was patented only in Japan. Interestingly, the patent for the Okuda cut is assigned to Hohoemi Brains and was issued in 2001 (application date was January 27, 2000). This is many years after Kazumi Okuda's death, so there must be an interesting story there.

Parameters for table sizes, pavilion angles and so on are contained in the patents but if you don't want to sift through it, it allows table sizes as low as 33%, pavilion angles as low as 37.5° and preferably no more than 40°, and crown angles satisfying the following inequality (around 31.5° for a 37.5° pavilion angle):

171.4883 - 3.74167pc ≤ 171.4315 - 3.75427p

where p is the pavilion angle and c is the crown angle.

The patents are over my head but maybe some of the people who really understand this kind of thing will find it interesting reading.
 
I thought I had one that worked in the HCA but found later that it had changed an angle on me. Every time I run one of these, I am warned of fisheye, a too small table, or danger of chipping from a too low crown angle.
 
Here is the Google translation of one of the more informative pages I''ve found on this.
 
I may be able to run the hCA on my desk top version SI
 
Do Cut Advisor results extend to these kinds of diamonds?

For the numbers below, I assumed a girdle thickness of 2%. I don''t know how accurate that is, but adjust as needed. Here are some examples in the following format: Depth Percentage, Table Percentage, Crown Angle, Pavilion Angle.

59.44, 38.00, 31.60, 37.50
58.83, 40.00, 31.60, 37.50
58.21, 42.00, 31.60, 37.50
57.59, 44.00, 31.60, 37.50
56.98, 46.00, 31.60, 37.50
56.36, 48.00, 31.60, 37.50
55.75, 50.00, 31.60, 37.50

58.77, 38.00, 29.73, 38.00
58.20, 40.00, 29.73, 38.00
57.63, 42.00, 29.73, 38.00
57.05, 44.00, 29.73, 38.00
56.48, 46.00, 29.73, 38.00
55.91, 48.00, 29.73, 38.00
55.34, 50.00, 29.73, 38.00

58.15, 38.00, 27.86, 38.50
57.63, 40.00, 27.86, 38.50
57.10, 42.00, 27.86, 38.50
56.57, 44.00, 27.86, 38.50
56.04, 46.00, 27.86, 38.50
55.51, 48.00, 27.86, 38.50
54.98, 50.00, 27.86, 38.50

57.60, 38.00, 25.98, 39.00
57.11, 40.00, 25.98, 39.00
56.62, 42.00, 25.98, 39.00
56.13, 44.00, 25.98, 39.00
55.65, 46.00, 25.98, 39.00
55.16, 48.00, 25.98, 39.00
54.67, 50.00, 25.98, 39.00

57.09, 38.00, 24.11, 39.50
56.64, 40.00, 24.11, 39.50
56.19, 42.00, 24.11, 39.50
55.75, 44.00, 24.11, 39.50
55.30, 46.00, 24.11, 39.50
54.85, 48.00, 24.11, 39.50
54.40, 50.00, 24.11, 39.50

56.63, 38.00, 22.23, 40.00
56.21, 40.00, 22.23, 40.00
55.81, 42.00, 22.23, 40.00
55.40, 44.00, 22.23, 40.00
54.99, 46.00, 22.23, 40.00
54.58, 48.00, 22.23, 40.00
54.17, 50.00, 22.23, 40.00
 
You are right - it will not work - these are very very flat stones - but the inverse inter relationship between crown and pavilion angles is there :)
 
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