ΔE 6.4, close: similar, with a visible difference side by side. Titan Buff is a little lighter, cooler than Quartz Skin.
Usually, if you are not matching paint already on the model. Close match (ΔE 6). Titan Buff is a little lighter, cooler than Quartz Skin.
The same difference applies the other way round: Quartz Skin is a little darker, 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 Quartz Skin on the colour wheel See Titan Buff on the colour wheel
All matches: Quartz Skin equivalents · Titan Buff equivalents