ΔE 18.8, loose: different enough that you should pick on purpose. Sapphire Blue is a little darker, more saturated, cooler than Purple Anodized Aluminum.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Sapphire Blue is a little darker, more saturated, cooler than Purple Anodized Aluminum.
The same difference applies the other way round: Purple Anodized Aluminum is a little lighter, 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 Purple Anodized Aluminum on the colour wheel See Sapphire Blue on the colour wheel
All matches: Purple Anodized Aluminum equivalents · Sapphire Blue equivalents