ΔE 17.0, loose: different enough that you should pick on purpose. Ion Blue is more muted, cooler than Mossy Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Ion Blue is more muted, cooler than Mossy Green.
The same difference applies the other way round: Mossy Green is 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.
See Mossy Green on the colour wheel See Ion Blue on the colour wheel
All matches: Mossy Green equivalents · Ion Blue equivalents