ΔE 29.6, loose: different enough that you should pick on purpose. Greenish Gold is noticeably lighter, much more muted, cooler than Copper Coin.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 30). Greenish Gold is noticeably lighter, much more muted, cooler than Copper Coin.
The same difference applies the other way round: Copper Coin is noticeably darker, much 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.
See Copper Coin on the colour wheel See Greenish Gold on the colour wheel
All matches: Copper Coin equivalents · Greenish Gold equivalents