Runic Gold vs Amber Green

How close are they?

ΔE 29.1, loose: different enough that you should pick on purpose. Amber Green is a little lighter, much more muted, cooler than Runic Gold.

Can I use Amber Green instead of Runic Gold?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 29). Amber Green is a little lighter, much more muted, cooler than Runic Gold.

Can I use Runic Gold instead of Amber Green?

The same difference applies the other way round: Runic Gold is a little darker, much more saturated, warmer.

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.