ΔE 10.1, fair: the same colour family, but not a straight swap. Gold 79 is a little darker than Fulgurite Copper.
Can I use Gold 79 instead of Fulgurite Copper?
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Gold 79 is a little darker than Fulgurite Copper.
Can I use Fulgurite Copper instead of Gold 79?
The same difference applies the other way round: Fulgurite Copper is a little lighter.
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.