Granite Stone vs Neutral Grey

How close are they?

ΔE 6.3, close: similar, with a visible difference side by side. Neutral Grey is a little darker than Granite Stone.

Can I use Neutral Grey instead of Granite Stone?

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

Can I use Granite Stone instead of Neutral Grey?

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

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.