ΔE 17.8, loose: different enough that you should pick on purpose. Dark Jade is a little darker, more muted, cooler than Guardian Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Dark Jade is a little darker, more muted, cooler than Guardian Green.
The same difference applies the other way round: Guardian Green is a little lighter, 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 Guardian Green on the colour wheel See Dark Jade on the colour wheel
All matches: Guardian Green equivalents · Dark Jade equivalents