Skeleton Bone vs Morghast Bone

How close are they?

ΔE 6.7, close: similar, with a visible difference side by side. Morghast Bone is more saturated than Skeleton Bone.

Can I use Morghast Bone instead of Skeleton Bone?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Morghast Bone is more saturated than Skeleton Bone.

Can I use Skeleton Bone instead of Morghast Bone?

The same difference applies the other way round: Skeleton Bone is 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.