ΔE 13.2, fair: the same colour family, but not a straight swap. Leviathan Blue is a little lighter, more saturated, cooler than Turnbull Turquoise.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Leviathan Blue is a little lighter, more saturated, cooler than Turnbull Turquoise.
The same difference applies the other way round: Turnbull Turquoise is a little darker, 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 Turnbull Turquoise on the colour wheel See Leviathan Blue on the colour wheel
All matches: Turnbull Turquoise equivalents · Leviathan Blue equivalents