ΔE 10.6, fair: the same colour family, but not a straight swap. Pylar Glacier is a little darker, more muted than Matt Marine Blue. They are different kinds of paint: AMMO by Mig Matt Marine Blue is an ink, glaze or transparent paint and Citadel Pylar Glacier is a one-coat contrast-style paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Pylar Glacier is a little darker, more muted than Matt Marine Blue. They are different kinds of paint.
The same difference applies the other way round: Matt Marine Blue is a little lighter, more saturated.
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 Matt Marine Blue on the colour wheel See Pylar Glacier on the colour wheel
All matches: Matt Marine Blue equivalents · Pylar Glacier equivalents