ΔE 8.0, close: similar, with a visible difference side by side. Stone Grey is a little lighter, warmer than Ruins Grey.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Stone Grey is a little lighter, warmer than Ruins Grey.
The same difference applies the other way round: Ruins Grey is a little darker, 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 Ruins Grey on the colour wheel See Stone Grey on the colour wheel
All matches: Ruins Grey equivalents · Stone Grey equivalents