62 % table- good crown and pav angles are....Rhino?

[strmrdr]

Date: 8/3/2007 12:44:40 PM
Author: iwannaprettyone
Strmr- what are your observations?

It looks like Jon posted the gem files.
I played with the stars and with the large table I liked the overall look better at 50 or even 45 than 60 but it made little difference.
In my opinion out of all the combos I played with 41/33/60t/80lgf(lenth 81.5 depth) was the most balanced combo and the one I would look for or something close too it.
Keep in mind this is with a theoretical stone with perfect symmetry.

Frankly I''d rather have a 41/34/56t/78-80lgf combo for the better balance of brightness and fire.

 

[strmrdr]

Date: 8/3/2007 12:00:57 PM
Author: iwannaprettyone
Not really, I am just fascinated by how many different variables there are...

I search 60-62% tables in house and found these two.

http://www.jamesallen.com/diamond.asp?b=16&a=12&c=77&cid=131&item=882657

http://www.jamesallen.com/diamond.asp?b=16&a=12&c=77&cid=131&item=936442

The funny thing is that I would reverse the GIA grade and grade the second very good and the first good based on my reasearch so far.

 

[Lynn B]

Interesting thread.

A question, please. Carat weight being the same, would an attractive diamond with a 60+ table APPEAR "larger" to the casual observer than one with a more typical smaller table?

 

[strmrdr]

Date: 8/3/2007 6:10:24 PM
Author: Lynn B
Interesting thread.

A question, please. Carat weight being the same, would an attractive diamond with a 60+ table APPEAR ''larger'' to the casual observer than one with a more typical smaller table?

Thats a tough one because finding a well cut 60% table stone too compare too is hard around here.
All I have done is compared AGS0 or equivalent smaller tabled stones to the typical to decent 60% diamonds and the smaller tabled stones looked bigger.
A 41/33/60t/80lgf would actually be a few percentage points bigger than a more typical ideal cut with the same girdle but not enough to matter much at 1ct.

 

[Garry H (Cut Nut)]

Date: 8/3/2007 6:16:46 PM
Author: strmrdr

Date: 8/3/2007 6:10:24 PM
Author: Lynn B
Interesting thread.

A question, please. Carat weight being the same, would an attractive diamond with a 60+ table APPEAR ''larger'' to the casual observer than one with a more typical smaller table?

Thats a tough one because finding a well cut 60% table stone too compare too is hard around here.
All I have done is compared AGS0 or equivalent smaller tabled stones to the typical to decent 60% diamonds and the smaller tabled stones looked bigger.
A 41/33/60t/80lgf would actually be a few percentage points bigger than a more typical ideal cut with the same girdle but not enough to matter much at 1ct.

A stone with those proportions would indeed appear a teensy bit larger - even if you compared it to a stone of 0.03ct larger diameter - the one that has the same diam but weighs more than the same diameter tolkowsky round with a 57% table

 

[JohnQuixote]

It also depends on lighting Lynn. Diamond graders use the 'flash' method for a quick estimation of table size. In fluorescent lighting especially you can rock the diamond and the table 'flashes' on and off (glare). 60-62%, which GIA considers a medium table, 'flashes' bigger than 56-57% and in some situations the diamond can seem spreadier...but as has been said...the make has a different look overall, mainly having to do with balance of fire vs brightness.

A problem with trying to compare these cuts in DiamCalc is optical symmetry (to the degree that it matters). I get to play with hundreds of 60/60 makes and have graded dozens in workshops. It's rare to see specimens with the kind of optical symmetry that's more or less expected on PS. When cutting a stone near-Tolkowksy a decent level of OS is often a 'happy accident' - I'm not necessarily talking about 'perfect' hearts & arrows or ducks & bunnies or whatever.

 

[Lynn B]

Hey guys (Storm, Garry, John) - thanks for the replies. I appreciate it.

I''d really like to see one of these diamonds in person one day. *sigh* So many diamonds... so little time!

 

[thevoodoowedo]

Where does one find the ags tables that John posted? Thanks

Btw, since one of the diamonds I''m interested in comes close to this discussion, would you mind commenting on it? Here are the specs:

measurements - 8.31 - 8.18 x 4.88mm
weight: 2ct
cert EGL

proportions
depth - 59.20%
table - 61%
crown angle 33.5 deg
pavilion angle 40.3 deg

clarity vs2
color h

cut grade egl very good

culet slightly large
girdle thin-thk
polish exc-vg

Price: 13,500

The comments I''ve gotten thus far were to skip it. What do you think? I''m in the market for something ~2ct and under $16,000

 

[strmrdr]

Date: 8/3/2007 11:06:24 PM
Author: thevoodoowedo
Where does one find the ags tables that John posted? Thanks

Btw, since one of the diamonds I''m interested in comes close to this discussion, would you mind commenting on it? Here are the specs:

measurements - 8.31 - 8.18 x 4.88mm
weight: 2ct
cert EGL

proportions
depth - 59.20%
table - 61%
crown angle 33.5 deg
pavilion angle 40.3 deg

clarity vs2
color h

cut grade egl very good

culet slightly large
girdle thin-thk
polish exc-vg

Price: 13,500

The comments I''ve gotten thus far were to skip it. What do you think? I''m in the market for something ~2ct and under $16,000

Comes out too an AGS5 on the charts.
The girdle is wavey and the culet is too big.
I think you were given good advise too skip it.

 

[Garry H (Cut Nut)]

Date: 8/3/2007 11:18:53 PM
Author: strmrdr
The girdle is wavey

 

[iwannaprettyone]

Date: 8/3/2007 11:38:44 PM
Author: Garry H (Cut Nut)

Date: 8/3/2007 11:18:53 PM
Author: strmrdr
The girdle is wavey

lol.

 

[vivianv]

Is there a way to use the gem advisor with a stone in hand? I'd be curious to see how the stone looks on Gem Advisor as opposed to my seeing it in RL.
The stone I have has these dimensions:
60% table
60.3 depth
32.5 crown angle
40.8 pav

I think the stone is very sparkly but I am not an expert by any stretch. It is rated very good on all counts on the GIA report and comes up a AGS1 on the chart.The HCA rating is 1.6 ,TIC range,with vg light return, ex fire, vg scint and ex spread.

 

[strmrdr]

Date: 9/22/2007 4:40:06 PM
Author: vivianv
Is there a way to use the gem advisor with a stone in hand? I''d be curious to see how the stone looks on Gem Advisor as opposed to my seeing it in RL.
The stone I have has these dimensions:
60% table
60.3 depth
32.5 crown angle
40.8 pav

I think the stone is very sparkly but I am not an expert by any stretch. It is rated very good on all counts on the GIA report and comes up a AGS1 on the chart.The HCA rating is 1.6 ,TIC range,with vg light return, ex fire, vg scint and ex spread.

Would need a 3d scan file from a sarin/helium too be accurate.
Buy an ideal-scope or ASET and look at it would be a better.
www.ideal-scope.com