ΔE 7.9, close: similar, with a visible difference side by side. Amberglow is a little darker, warmer than Martian Ironcrust. They are different kinds of paint: Citadel Martian Ironcrust is a technical paint or medium and Green Stuff World Amberglow is a one-coat contrast-style paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Amberglow is a little darker, warmer than Martian Ironcrust. They are different kinds of paint.
The same difference applies the other way round: Martian Ironcrust 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.
See Martian Ironcrust on the colour wheel See Amberglow on the colour wheel
All matches: Martian Ironcrust equivalents · Amberglow equivalents