ΔE 7.8, close: similar, with a visible difference side by side. Light Turquoise is more saturated, cooler than Blue Gray.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Light Turquoise is more saturated, cooler than Blue Gray.
The same difference applies the other way round: Blue Gray is more muted, warmer.
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 Blue Gray on the colour wheel See Light Turquoise on the colour wheel
All matches: Blue Gray equivalents · Light Turquoise equivalents