ΔE 17.2, loose: different enough that you should pick on purpose. Violet Vamp is a little lighter, much more saturated, warmer than Lapislazuli.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Violet Vamp is a little lighter, much more saturated, warmer than Lapislazuli.
The same difference applies the other way round: Lapislazuli is a little darker, much more muted, 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 Lapislazuli on the colour wheel See Violet Vamp on the colour wheel
All matches: Lapislazuli equivalents · Violet Vamp equivalents