ΔE 17.2, loose: different enough that you should pick on purpose. Sombre Grey is a little lighter, more muted, cooler than Amulet Purple.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Sombre Grey is a little lighter, more muted, cooler than Amulet Purple.
The same difference applies the other way round: Amulet Purple is a little darker, 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 Amulet Purple on the colour wheel See Sombre Grey on the colour wheel
All matches: Amulet Purple equivalents · Sombre Grey equivalents