ΔE 8.1, close: similar, with a visible difference side by side. Abyssal Turquoise is more saturated than Terror Blue-Grey.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Abyssal Turquoise is more saturated than Terror Blue-Grey.
The same difference applies the other way round: Terror Blue-Grey 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 Terror Blue-Grey on the colour wheel See Abyssal Turquoise on the colour wheel
All matches: Terror Blue-Grey equivalents · Abyssal Turquoise equivalents