ΔE 11.7, fair: the same colour family, but not a straight swap. Cerulean Blue Hue is a little darker, more saturated than Soulstone Blue. They are different kinds of paint: Citadel Soulstone Blue is a technical paint or medium and Golden Cerulean Blue Hue is an ink, glaze or transparent 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 12). Cerulean Blue Hue is a little darker, more saturated than Soulstone Blue. They are different kinds of paint.
The same difference applies the other way round: Soulstone Blue is a little lighter, 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 Soulstone Blue on the colour wheel See Cerulean Blue Hue on the colour wheel
All matches: Soulstone Blue equivalents · Cerulean Blue Hue equivalents