Aquamarine vs Corsa Gray

How close are they?

ΔE 17.9, loose: different enough that you should pick on purpose. Corsa Gray is a little lighter, much more muted, cooler than Aquamarine.

Can I use Corsa Gray instead of Aquamarine?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Corsa Gray is a little lighter, much more muted, cooler than Aquamarine.

Can I use Aquamarine instead of Corsa Gray?

The same difference applies the other way round: Aquamarine is a little darker, much more saturated, warmer.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.