ΔE 10.0, fair: the same colour family, but not a straight swap. Turquoise is a little lighter, more saturated than Steel Shadow.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Turquoise is a little lighter, more saturated than Steel Shadow.
The same difference applies the other way round: Steel Shadow is a little darker, more muted.
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 Steel Shadow on the colour wheel See Turquoise on the colour wheel
All matches: Steel Shadow equivalents · Turquoise equivalents