Levels of pressure-sensitivity in feather inclusions?

[Finally!]

You may recall that I was investigating a 60:60 stone from BN that got an HCA score of 1.3. I specifically asked to have the stone checked to see if the long feather in the pavilion plot touches the girdle, which I learned here could indicate that the stone could be pressure-sensitive. Turns out, it is. They told me that the stone rates a "2" on pressure sensitivity, with "4" being something they would have rejected. They said that BN will sell "2" and "3"-level pressure sensitive stones.

I've ruled this stone out because it has only MB Fluor, but I'm still curious about this concept of grading pressure-sensitivity.

What do you folks think of this? Is this a BN thing? Do prongs apply pressure in the direction that could extend the feather or break the stone?

 

[Garry H (Cut Nut)]

Date: 10/8/2008 12:02:28 AM
Author:Finally!
You may recall that I was investigating a 60:60 stone from BN that got an HCA score of 1.3. I specifically asked to have the stone checked to see if the long feather in the pavilion plot touches the girdle, which I learned here could indicate that the stone could be pressure-sensitive. Turns out, it is. They told me that the stone rates a ''2'' on pressure sensitivity, with ''4'' being something they would have rejected. They said that BN will sell ''2'' and ''3''-level pressure sensitive stones.

I''ve ruled this stone out because it has only MB Fluor, but I''m still curious about this concept of grading pressure-sensitivity.

What do you folks think of this? Is this a BN thing? Do prongs apply pressure in the direction that could extend the feather or break the stone?

Diamonds, especially center stones, rarely break when setting. Once set, the feather on the pavilion side would not be any sort of risk. But a high 4 prong setting would be silly.