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Spread percentage

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risingsun

Ideal_Rock
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Can someone explain what the +/_ numbers mean? I have read the tutorial, but don''t really understand how the percentages define the spread. I have been looking at some stones and this parameter has me baffled. Thanks for the help.
 

Garry H (Cut Nut)

Super_Ideal_Rock
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It is a comparitive figure for the surface area of a stone compared to a Tolkowsky round with a thin girdle.

+1% = a spread that would be 0.01ct bigger for a 1ct size

-15% is very small - and typical for a princess with an appropriate safe girdle thickness for example.
 

risingsun

Ideal_Rock
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When looking for an ideal cut stone, what range of percentages is acceptable?
 

Bunnifer

Shiny_Rock
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Date: 1/3/2007 10:59:57 PM
Author: Garry H (Cut Nut)
It is a comparitive figure for the surface area of a stone compared to a Tolkowsky round with a thin girdle.



+1% = a spread that would be 0.01ct bigger for a 1ct size


-15% is very small - and typical for a princess with an appropriate safe girdle thickness for example.

Garry, what is the typical range for surface area percentage in princesses with an appropriate safe girdle thickness? Do many princesses stay true to their ideal diameters (e.g., 6.5mm x 6.5mm for a 1.5 carat princess)?
 
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