ΔE 8.8, close: similar, with a visible difference side by side. Calth Blue Clear is a little darker, warmer than Sapphire Gem.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Calth Blue Clear is a little darker, warmer than Sapphire Gem.
The same difference applies the other way round: Sapphire Gem is a little lighter, cooler.
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 Calth Blue Clear on the colour wheel
All matches: Sapphire Gem equivalents · Calth Blue Clear equivalents