infomation on crown depth and angle form GIA

[yeewl]

Hello,

Recently I bought a new book written by Renee Newman iamond Handbook.
Not sure if anyone had come acrossed it?

Anyway, I saw this particular topic (page 57) regarding Pavilion Depth and Pavilion angle taken from GIA Diamond Grading Course.
Just wanted to know does anyone has more infomation on crown depth and crown angle from GIA diamond grading course?
I would be very grateful if anyone can provide me with more details.

Oh by the way, is it really that accurate just based on that?

Pavilion depth Pavilion angle
Approximately:
40.0 38.7
40.5 39.0
41.0 39.4
41.5 39.7
42.0 40.0
42.5 40.4
43.0 40.7
43.5 41.0
44.0 41.3
44.5 41.7
45.0 42.0

Kind regards

 

[strmrdr]

Dont know what is in the gia grading course but...

crown height isnt enough info to calculate crown angle.
The table is the other variable.
The table will often vary in size depending on which way you measure it.
Getting angles from % is problematic at best.

The pavilion depth to pavilion angle will vary with culet size.
Just depth isnt enough info to calculate it.

Percentages are often badly rounded on many certs so they are pretty useless.

 

[strmrdr]

For example:
45% pavilion

culet size_____P. angle
pointed/none___42.01
v-small________42.06
small__________42.11
medium________42.27
s-large________42.73
large_________43.5
v-large________45.0
e-large________47.2