also a fair amount of gold's thing was that is was just weird in comparison to other metals.
Does not corrode , oxidize etc under normal use - this is similar to how the sun was often considered "pure" with in part has to do with its blatant otherness.
found in metal form. - and this is HUGE. this is a little fleck or nugget that does not fit in with the soil, stone around it.
and it shines in a similar spectrum to solar color-if you have a gold nugget in pile of similar sized pebbles it stands out in the same kind of way the sun stands out. and under firelight more-so.

something similar could be created with copper alloys (brass more than bronze) but they were harder to work and didn't maintain their sheen.


so similar
associations with purity
contrast to surroundings/otherness
and color similarity

so yeah It not really surprising gold came to be associated with the sun.