ΔE 13.8, fair: the same colour family, but not a straight swap. Hydra Turquoise is a little lighter, more muted, warmer than Crystal Cavern.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Hydra Turquoise is a little lighter, more muted, warmer than Crystal Cavern.
The same difference applies the other way round: Crystal Cavern is a little darker, more saturated, 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 Crystal Cavern on the colour wheel See Hydra Turquoise on the colour wheel
All matches: Crystal Cavern equivalents · Hydra Turquoise equivalents