ΔE 19.1, loose: different enough that you should pick on purpose. Pale Blue Dot is a little lighter, much more saturated, warmer than Sapphire Gem.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Pale Blue Dot is a little lighter, much more saturated, warmer than Sapphire Gem.
The same difference applies the other way round: Sapphire Gem is a little darker, much more muted, 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 Pale Blue Dot on the colour wheel
All matches: Sapphire Gem equivalents · Pale Blue Dot equivalents