ΔE 14.8, fair: the same colour family, but not a straight swap. True Blue is more muted, cooler than Sapphire Gem.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). True Blue is more muted, cooler than Sapphire Gem.
The same difference applies the other way round: Sapphire Gem is more saturated, 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 Sapphire Gem on the colour wheel See True Blue on the colour wheel
All matches: Sapphire Gem equivalents · True Blue equivalents