ΔE 7.7, close: similar, with a visible difference side by side. Fluor Violet is more saturated than Magos Purple. They are different kinds of paint: Citadel Magos Purple is a one-coat contrast-style paint and Green Stuff World Fluor Violet is a fluorescent or effect 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). Fluor Violet is more saturated than Magos Purple. They are different kinds of paint.
The same difference applies the other way round: Magos Purple is more muted.
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 Magos Purple on the colour wheel See Fluor Violet on the colour wheel
All matches: Magos Purple equivalents · Fluor Violet equivalents