Size difference thats discernible?

[pinkrose]

Can you see a difference of .10 mm in a 1 carat. That seems like such a tiny difference but I read here that its discernible.

 

[Garry H (Cut Nut)]

If one diamond was 6.4mm and one was 6.5mm in earrings you would not see it, and if they were either side of a a say 1.5ct center stone and tilted away from each other you would not see the difference.

But hold them side by side and show 10 people and 5 might notice it if they were looking closely.