What is a good ratio for a the top of a round brilliant diamond, length to width?

[abefroman]

What is a good ratio for a the top of a round brilliant diamond, length to width? (this is just across the top and not the depth.

For example
A width of 5.00mm and length 5.05MM having a ratio of 1.01
and
A width of 5.00mm and length 5.25MM having a ratio of 1.05

Is there a certain ratio I want to stay under?

TIA

 

[oldminer]

a great round is "round", period. a good round will look round, but vary a bit like 5.0-5.1, a lower quality of cut would be happening with 5.0-5.2.

 

[abefroman]

Most of the ones I have been looking at are between 2-4 hundredths of a millimeter difference.

Should I try to find one with exactly the same width and length?

TIA

 

[Garry H (Cut Nut)]

try this

http://www.gemology.ru/cut/english/symmetry/5.htm

 

[Serg]

Date: 7/4/2009 4:58:16 PM
Author: Garry H (Cut Nut)

try this

http://www.gemology.ru/cut/english/symmetry/5.htm

It is old standards. 4% for 1ct diamond is Too much now.
0.02mm is quite achievable in last years . Many cutters try be in range 0.5%-1% or even below 0.02mm