shape
carat
color
clarity

How much of a problem can 40.6 be?

Kim N

Ideal_Rock
Premium
Joined
Oct 6, 2005
Messages
6,388
I'm considering a recut with a 40.6 average pavilion angle (and 34.6 crown), but the cutting will be done to a tolerance of 0.2, which means that some of the pavilion mains may be at 40.4 or 40.5. How much of a problem can this be in terms of obstruction?
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
There is a big jump at aprox. 40.45 you want to idealy keep all the mains over. If the lgf% is 77 or over sometimes one or 2 slightly under is not a huge issue but less than ideal.
 

Kim N

Ideal_Rock
Premium
Joined
Oct 6, 2005
Messages
6,388
Thanks, @Karl_K. So it sounds like I'll probably want to keep it to 40.7 average to avoid any of the mains going under 40.45. LGF is around 70%.
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Thanks, @Karl_K. So it sounds like I'll probably want to keep it to 40.7 average to avoid any of the mains going under 40.45. LGF is around 70%.

yea sounds good
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
18,422
Generally if there is a variation in pavilion angle - there is a complimentary variation in crown angel and it is less of an issue, or no issue at all.
I personally prefer 40.6 and 34. The only people who would not are short sighted and look at diamonds from crazy close up.
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Generally if there is a variation in pavilion angle - there is a complimentary variation in crown angel and it is less of an issue, or no issue at all.
I personally prefer 40.6 and 34. The only people who would not are short sighted and look at diamonds from crazy close up.

Its arguable one way or the other......
Except its being cut with 70% lowers if ones of those dip to 40.4 your going to see it.
 

Kim N

Ideal_Rock
Premium
Joined
Oct 6, 2005
Messages
6,388
Generally if there is a variation in pavilion angle - there is a complimentary variation in crown angel and it is less of an issue, or no issue at all.
I personally prefer 40.6 and 34. The only people who would not are short sighted and look at diamonds from crazy close up.
Unfortunately, I'm pretty near-sighted and do look at diamonds close up. :bigsmile:
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
What table size are you having it cut to?
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Unfortunately, I'm pretty near-sighted and do look at diamonds close up. :bigsmile:
With the big arrows from the 70% lgf its going to be very contrasty up close no matter what the pavilion angle is cut to.
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
40.7 at ~8 inches.

407.jpg

40.4 would be that dark at 15+ inches and beyond where you cant distinguish the arrows as arrows and it just looks dark.
 

Kim N

Ideal_Rock
Premium
Joined
Oct 6, 2005
Messages
6,388
40.7 at ~8 inches.
Wow, thank you for modeling this. I think I'd be very happy if it looked like this at ~8 inches. Knowing there's a tolerance of 0.2, would you expect to see any leakage with 40.7 average?
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
Wow, thank you for modeling this. I think I'd be very happy if it looked like this at ~8 inches. Knowing there's a tolerance of 0.2, would you expect to see any leakage with 40.7 average?
no more than is present in any round.
 

flyingpig

Ideal_Rock
Premium
Joined
Nov 7, 2015
Messages
2,975
54/34.9/40.5 76 LGH
I am sure some PAs dip to 40.4
Contrasty, Yes
Darkness or Obstruction Issue IRL, No
 

Karl_K

Super_Ideal_Rock
Trade
Joined
Aug 4, 2008
Messages
14,634
54/34.9/40.5 76 LGH
I am sure some PAs dip to 40.4
Contrasty, Yes
Darkness or Obstruction Issue IRL, No

to much obstruction to make that call.
The issue is mains staying dark under less obstruction instead of going bright.
 
Be a part of the community Get 3 HCA Results
Top