Spread Index

[wonka27]

My apologies! Right number, wrong terminology. Should have been more careful.

 

[Superidealist]

Don't worry. It's not like it's official terminology. It's just something I made up. I just didn't want people to get confused.

 

[wonka27]

Thanks. I just did the formula that would give the "ideal" diameter for their stone. I figure that is what they wanted to know.

It is a fun formula to play with!

 

[researcher]

I was too tired last night and made the same mistake about thinking what you were calling the spread index was for the diameter. Now I get why the numbers didn't come out the same! Very cool. Thanks for sharing!

 

[lsmathis1]

Ahha! Now this makes a lot more sense. Thanks for helping...and thank you for clearing that up Superidealist and running my numbers as well. Looks like my little babies a bit fat

No problem though - it's perfect to me!

Thanks again,
Lisa

 

[Superidealist]

Your diamond is no slouch, Lisa. Its spread index is near that of the average Hearts on Fire diamond. (link)

 

[lsmathis1]

Oh wow, thanks - that is a very interesting and educational chart you have put together. I now understand even more about this little sparklers!

When we were looking at the diamond before purchasing I was just blown away by it's visual performance...but still tend to get fixated on the "numbers". Probably so because I'm still awaiting it's arrival and can't see it in person - just in memory(BF has it to formally present to me soon). Anyway, thanks again for helping me understand what all this means - how it works and how mine stacks up. I can't wait to show it when it arrives on my anxiously awaiting hand.

Lisa

 

[Lynn B]

----------------
On 8/18/2004 10:34:48 PM stretch4 wrote:

Lynn,

6.518...very nice!!!

Michelle----------------

Michelle,

THANKS! You sure made it seem easy. I'm still scratching my head!

Lynn

 

[lenhejo]

Hi everyone,

I am having difficulty with the calculation:

My diamonds measurements are 9.40-9.44-5.76
Carat - 3.095

Could you please include the numbers on how you figured it out.

Thanks.

 

[Superidealist]

Spread Index: 6.46
"Ideal" Diameter for 3.095ct: 9.47mm
"Ideal" Weight for 9.42mm: 3.04ct

 

[Lynn B]

You guys are AMAZING!!!!

Lynn

 

[Rowan]

Thanks Superidealist!!! It's nice to know my stone is ideal and fat free!

 

[Todd07]

Wow, I'm good at my math /idealbb/images/smilies/read.gif but had trouble with this until I found an example in another post. Hope the below helps other readers check the fitness of their diamond.





My stone: 1.6 c, 7.6 ave diameter





Spread Index = (average diameter) / ((carat weight)^(1/3))


= 7.60 / ((1.6)^(1/3))


= 7.6 / (1.169607)


= 6.498





Tip - use the excel spreadsheet "Power" function if you don't have a good calculator "=+(7.6)/POWER(1.6,(1/3))"





Can't wait to see the diamond at the appriasers next week




(edited to delete comparison to ideal)

 

[Superidealist]

Just to reiterate, I recommend not dividing by 6.50 as Magna had suggested. This implies that 6.50 is the standard for perfection. If you notice, I've been very careful to include the word ideal in quotation marks throughout this thread. That's because I don't believe that there is such a thing as an ideal diameter or carat weight. Dividing by 6.50 locks us in to the mindset that there is such a thing as the perfect diameter for a diamond of a given carat weight. I just don't believe that is true.

 

[msbennie]

How do you "raise to the power of 1/3"? I tried using the scientific calculator but that doesn't work either. I would appreciate if someone would compute my spread index.

Average Diameter: 6.905
Carat: 1.194

Thanks!

 

[wonka27]

----------------
On 8/21/2004 10:19:35 AM msbennie wrote:

How do you 'raise to the power of 1/3'? I tried using the scientific calculator but that doesn't work either. I would appreciate if someone would compute my spread index.

Average Diameter: 6.905
Carat: 1.194

Thanks!----------------

MsBennie -

I think I have all the terminology right and have calculated your numbers. For your diamond:

Spread Index: 1.001341504
Ideal Diameter for 1.194 cts.: 6.895749325 mm

As you can see...you have an ever so slightly larger diamond compared to the "ideal" measurements at your carat weight

 

[motcs]

It seems like some people are having some difficulties with the math, so please find attached a simple Excel calculator here:

http://home.comcast.net/~moquilok/diamond_spread_calc.xls

 

[msbennie]

Thanks Wonka!

 

[alexah]

Thanks so much motcs! That excel calculator's terrific

My RHR stone (the one i recently bought) comes out at 0.00% fat - the avg diameter is slightly greater than the "ideal"

 

[Superidealist]

Nice work, motcs.