Gemstone Red vs Red Queen

How close are they?

ΔE 8.9, close: similar, with a visible difference side by side. Red Queen is a little darker, warmer than Gemstone Red.

Can I use Red Queen instead of Gemstone Red?

Usually, if you are not matching paint already on the model. Close match (ΔE 9). Red Queen is a little darker, warmer than Gemstone Red.

Can I use Gemstone Red instead of Red Queen?

The same difference applies the other way round: Gemstone Red 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.