Can anyone help figure out pavilion angle?

[Pimberly]

I know there’s a thread around here somewhere with a math equation, but I’m horrendous at math. Can anyone help me figure out the pavilion angle? These are the only numbers I have unfortunately:

Total depth: 62.2%
Table: 55%
Crown angle: 34.5
Pavilion depth: 43.7%

If this is possible, I’d greatly appreciate it!

 

[david b]

The easiest would be to ask the diamond owner or the vendor to give you the pavillion angle.
There is this optical scanner called Sarin or Ogi that meassures all diamond's angles

 

[Texas Leaguer]

I believe it will be 41.15

Do you have a GIA report number?

 

[gm89uk]

I get the same number, wth a 3% girdle.
As GIA doesn't give .7 in pavilion depth, unlikely the poster has one.

 

[diamondseeker2006]

Don't buy if the stone is not GIA or AGS graded. A 41+ pavilion angle would rule this stone out anyway.

 

[Pimberly]

Thank you everyone! It was an old Tiffany certificate before they included the pavilion angle. I’ll pass!

 

[OoohShiny]

Do a search for threads started by oldminer - he posted the math thread IIRC

 

[sledge]

For the OP, or those that may stumble along here later, here is a post I shared in another thread and I am sharing again here so you will know how to do the math. Don't worry, Excel can do your heavy lifting.

FWIW, 41.15 is what it calculates to as already confirmed by @Texas Leaguer and @gm89uk.

If you find yourself needing to convert crown or pavilion heights to angles you can use these formulas that @asblackrock provided in the original thread below.

My work is limited to the Excel formulas only.

https://www.pricescope.com/communit...-calculating-crown-and-pavilion-angles.20396/



The tan-1 function is equivalent to Excel's ATAN function. Also, because of the radians thing I noted earlier, you want to output your answer to degrees so we will use the DEGREE function as well. All nested together it looks like this:

• Excel version: =DEGREES(ATAN(43.1/50))
  • where 43.1 is actual pavilion height shown on report

Keep in mind, because the way GIA rounds/approximates/calculates pavilion & crown heights you sometimes get funky results vs if you try this. Point in case is if you input this particular stone's pavilion height of 42.5. Reality is 40.6 is closer to 42.8% but GIA tends to round that value down to 42.5, which gives a bunk result in Excel.

• Excel version: =DEGREES(ATAN(16.2/((1-(53/100))*50)))
  • where 16.2 is reported crown height
  • where 53 is reported table

 

[Karl_K]

Not all scanners measure, calculate, round or report the pavilion % the same way then some reports do other things with it after that so the number is pretty much useless.