shape
carat
color
clarity

Different carat weights for different stones?

Status
Not open for further replies. Please create a new topic or request for this thread to be opened.

SparkleRx

Rough_Rock
Joined
Mar 27, 2005
Messages
66
Hi,

I am in the process of getting a custom set made (ring, earrings, necklace, bracelet) similar to the Tiffany Legacy collection. I was at Tiffany''s today looking at different sizes of stones. I want pink sapphires for my set. The store didn''t have many sapphires in stock so I had to try different stones on (tanzanite, aquamarine, tourmaline, diamond) to get a feel for what size I wanted.

What I was noticing was a 2.0 ctw of a diamond was a totally different size than a 2.0 ctw of a pink sapphire. And a 1.50 ctw of an aquamarine was a totally different size than a 1.50 ctw of a tanzanite. And so forth. The sales associate said the different gems of same ctw have different measurments (and are therefore of different physical size even though they have the same ctw size).

Now this makes my custom made process even harder, since not many jewelers are available by me and I am going to do this process through the internet. I was hoping to tell whomever I chose to do my set specific ctw sizes ...but if I base the ctw size off of say, a diamond, I will end up with a "smaller" pink sapphire than expected.

**My question is what other gemstones would be equivalent to the ctw ''size'' of the pink sapphire. (the Tiffany''s sales associate wasn''t able to answer). I was hoping to base my desired ctw sizes off of diamonds (since there is an abundance of those for me to try on), but now I need to base my desired ctw size off of another stone that is equivalent to the measuring guidelines of a pink sapphire. My local Tiffany''s only had 2 pink sapphire legacy rings for me (one size was not even close to the size I am looking for and they didn''t have any other pink sapphires in rings, earrings, neclaces, or braelets in the store for me to compare).

It seemed that the pink sapphire was smaller than an equivalent ctw size of a diamond.

Thanks in advance for any advice out there!
 
A 1 carat sapphire is smaller than a 1 carat diamond because sapphire is denser. In addition, colored gemstones are cut deeper than diamond to retain color, further reducing their face-up size for the weight. When trying rings on, ask for the millimeter measurement of the stone, whether it be diamond, sapphire, whatever. Then you can get an idea of what millimeter size you want when you order online.
 
general rule of thumb that will get you close..
diamond weight x 1.5 ~= same size sapphire of the same shape.
Then you check the mm measurements too nail it down.

~= means approximately equals and takes into account different cutting angles and material density under near ideal conditions which is why its a rough approximation only.
 
Urseberry - thanks so much for the info. Makes sense now that I think about it. Good idea about getting the mm size also

Strmrdr - thanks for the quick cheat calculation. That will come in handy as a quick reference.

Do you have a quick estimated calculation for blue sapphire, tanzanite, aquamarine and/or other gems VS. the pink sapphire? The reason I ask is because I am going to base my custom set off of the Legacy, which has a halo, so I would like to try one of the existing coloured legacys to get a feel of what size I want. This may be hard to do with a diamond since the diamond is the same color as the surrounding halo of diamonds.

Are the coloured gems significantly cut deeper? I am just wondering how much this will affect my custom set since I don''t want a ring that sits too far up off my finger.
 
yes colored stones in general are cut deeper, I know of no rule for the other stones.
You just cant go by specific gravity(density) the critical angle also has too be considered.
 
Did some hunting and some math dont take these too the bank just a very very rough starting point,,,,,
diamond weight x 1.35 ~= same size tanzanite of the same shape.
diamond weight x .94 ~= same size aquamarine of the same shape.
 

In addition most colored gems have bellies - i.e. they bulge out in the pavilion, and this can add 15% extra weight.



And darker stones appear smaller.



e.g. when making alternating dark sapphire / round diamond suites the sapp should be 9% bigger in diameter to appear the same size. For mid to light blue sapphire the diamonds need only be 4-5% smaller.

 
Date: 1/27/2008 1:26:30 AM
Author: SparkleRx
Urseberry - thanks so much for the info. Makes sense now that I think about it. Good idea about getting the mm size also

Strmrdr - thanks for the quick cheat calculation. That will come in handy as a quick reference.

Do you have a quick estimated calculation for blue sapphire, tanzanite, aquamarine and/or other gems VS. the pink sapphire? The reason I ask is because I am going to base my custom set off of the Legacy, which has a halo, so I would like to try one of the existing coloured legacys to get a feel of what size I want. This may be hard to do with a diamond since the diamond is the same color as the surrounding halo of diamonds.

Are the coloured gems significantly cut deeper? I am just wondering how much this will affect my custom set since I don''t want a ring that sits too far up off my finger.
Colored Stones have their own rules for cutting..., as color is objective!!

But please take into consideration that the Legacy center stone is a patented cut and is limited to the range it can be cut!
 
Status
Not open for further replies. Please create a new topic or request for this thread to be opened.
GET 3 FREE HCA RESULTS JOIN THE FORUM. ASK FOR HELP
Top