Why do some diamonds look the same size even though they are not?

[TimothyLYork]

Today I was looking at the Tiffany Legacy diamond ring. It is a cushion cut. My question is why would a 1.25ct look just as large as their 1.57ct stone?

 

[IrishEyes]

It all boils down to the cut on each stone. Usually it is a combination of depth and spread that gives the look or lack thereof of size. I''ve seen this many times. I will see a .85 stone look the same as a 1 carat, etc. It''s frustrating when you are looking to upgrade because many times I will be looking for something bigger than my .75 and the jeweler will say "oh I have the most beautiful 1 carat or .95 carat here" and then when they are held next to each other, they look the same size!! Why pay for that?!

Look for the most ideal combination of numbers you can find, but remember not to solely rely on those numbers and use your eyes as well. a well cut diamond will display a size it is supposed to, not look smaller than it actually is....

 

[hoorray]

CTW is a Weight, not a visual dimension. Some stones are cut deeper than others, so a lot of their weight is in the depth of the stone, not in the diameter. MY guess is that you are comparing stones with two very different depths.

 

[JohnQuixote]

Diamonds cut too shallow may appear larger than they should, while diamonds cut too deep cut may look smaller. It is a matter of depth. Too shallow and too deep are both undesirable.

Use millimeter measurements and consider girdle thickness when judging proper spread for carat weight.

This chart from cflutist is a helpful guide for a number of shapes.