Worn Stone vs Beige Grey

How close are they?

ΔE 6.3, close: similar, with a visible difference side by side. Beige Grey is a little darker, warmer than Worn Stone.

Can I use Beige Grey instead of Worn Stone?

Usually, if you are not matching paint already on the model. Close match (ΔE 6). Beige Grey is a little darker, warmer than Worn Stone.

Can I use Worn Stone instead of Beige Grey?

The same difference applies the other way round: Worn Stone is a little lighter, 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.