Crown Angles/Pav Angles - simulation

[schrum]

Hello all - Thank you for your help sofar - this site is really cool and a lot of good info has helped me a lot sofar.

I am considering the following:

Round
8.06 x 8.12 x 4.96
2.00 ct
Depth: 61.2
Table: 61
Girdle: Medium Fac
Culet: None
Polish: very good
Symm: Very Good
Flour: Med Blue
VS1 F

GIA cert

But the crown angles >35.

Is there any way to get some information/ simulated analysis of this ? Also, what does it mean if the angles are higher and how does it affect the cut etc. The price is good, but not sure if it is good enough to justify the crown issue - so trying to make up my mind here.

Thanks in advance for your help.
Michael

 

[Rhino]

the information is too general but crown angles greater than 35 doesn't sound promising. You don't want to base a cut judgement on a GIA Report alone. Insist on a Sarin or MegaScope analysis.

Rhino

 

[dimonbob]

Hi Michael,
This is a perfectly good example of cutters greed or stupidity. If they would have lowered the crown angles down just a bit, the table would have been within ideal standards, the crown would be the same and they would not have received those comments on the diamond grading report.

Of course it would have been just under 2.00 carats with less profit. Maybe not stupid but for sure a Greed factor!
High crown angles will change the look of the diamond and not for the better.

 

[schrum]

Hey - thank you both - how much of a problem is it though - I reckon the price is 15%-20% lower than would have been with a 35 crown angle - will the difference be noticable ? other effects ?

Thanks again for your help - I will make sure I get some more analysis prior to purchase.

Michael

 

[schrum]

All,

Was wondering if anyone could help me with this - I am looking to buy on Monday - will post sarin on monday.

Thanks.
Michael

 

[Richard Sherwood]

-----------
Is there any way to get some information/ simulated analysis of this?
Also, what does it mean if the angles are higher and how does it
affect the cut etc. The price is good, but not sure if it is good
enough to justify the crown issue - so trying to make up my mind here.
-----------

Hi Mike. Without crown/pavilion height/angles it is impossible to create a DiamCalc profile on your stone, because the possibilities and consequent Light Return Analysis' are thousandfold.

I did, however, do two hypothetical profiles on similar stones which mainly differed on their crown angles. The one with the heavier light leakage (white area inside table) has a 35.5 degree crown angle, and the other one has a 34.5 degree angle. It shows you how much difference one degree can make, if it's not compensated for with a corresponding change in pavilion angle.

These two stones would probably go for relatively the same amount of money on the market. Not many dealers are discounting as heavily as you hypothesize just because of a difference in crown angles. That's why it's important to have an optical analysis performed on your prospective stone, as well as the traditional methods of interpreting cut.

-----------
IdealScope- In general, the darker pink areas indicate areas of greater light return, with the lighter pink areas indicating areas of lesser light return. The black areas indicate areas of greater contrast, with the gray areas indicating areas of lesser contrast. The white areas indicate areas of light leakage. A good explanation of the IdealScope image along with examples can be found at https://www.pricescope.com/idealscope_indx.asp
-----------

 

[Richard Sherwood]

...

 

[Richard Sherwood]

...

 

[nycguy]

how did you know that the crown was above 35? does gia now give that information on their certs?

 

[Richard Sherwood]

GIA will usually put in the comments section if the average crown angle is greater than 35 degrees, or less than 30 degrees.