Kunzite Alchemy vs Celestial Violet

How close are they?

ΔE 21.0, loose: different enough that you should pick on purpose. Celestial Violet is noticeably lighter, more muted, cooler than Kunzite Alchemy.

Can I use Celestial Violet instead of Kunzite Alchemy?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 21). Celestial Violet is noticeably lighter, more muted, cooler than Kunzite Alchemy.

Can I use Kunzite Alchemy instead of Celestial Violet?

The same difference applies the other way round: Kunzite Alchemy is noticeably darker, more saturated, 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.