ΔE 8.6, close: similar, with a visible difference side by side. Karak Stone is a little darker, more saturated than Dust.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Karak Stone is a little darker, more saturated than Dust.
The same difference applies the other way round: Dust is a little lighter, more muted.
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 Dust on the colour wheel See Karak Stone on the colour wheel
All matches: Dust equivalents · Karak Stone equivalents