ΔE 19.5, loose: different enough that you should pick on purpose. Rusty Metal is a little darker, more saturated, warmer than Peridot Alchemy.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Rusty Metal is a little darker, more saturated, warmer than Peridot Alchemy.
The same difference applies the other way round: Peridot Alchemy is a little lighter, more muted, cooler.
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 Peridot Alchemy on the colour wheel See Rusty Metal on the colour wheel
All matches: Peridot Alchemy equivalents · Rusty Metal equivalents