ΔE 18.1, loose: different enough that you should pick on purpose. Ancient Copper is a little darker, more saturated, warmer than Citrine Alchemy.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Ancient Copper is a little darker, more saturated, warmer than Citrine Alchemy.
The same difference applies the other way round: Citrine Alchemy is a little lighter, 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 Citrine Alchemy on the colour wheel See Ancient Copper on the colour wheel
All matches: Citrine Alchemy equivalents · Ancient Copper equivalents