Why is the measurements can vary for a same sized carat?

[Diamondfresh]

Is there any catch? Where all 3 dimensions are shorter.

 

[lovedogs]

because carat weight doesn't actually matter for how big a stone looks. It's all about the mm size itself, which is what you see when you look at the stone. Stones that are cut deeper will be smaller mm measurements versus stones that are less deep.
That's one reason we recommend avoiding stones that are more than 62.4 deep.

 

[Karl_K]

3.99mm > 3.96mm but they could have the exact same mm numbers and different weight even in an RB.

 

[Acinom]

Carat is a measurement of weight. Not of size. A diamond can be cut for excellent light return and have certain measurements. If a diamond is cut too shallow or too deep it will look larger or smaller from the top (but not look better in terms of light return)

 

[Karl_K]

 

[GearGirly]

Just like people, same weight but totally different build!