system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is gold shiny-yellow but most of the other metals have a silvery color?
gpt
Basically, because gold has an electron transition (two different levels the electrons can be in) that corresponds to blue light wavelengths, so gold absorbs a little blue and the reflected light looks yellow as a result.

Most metals don't absorb within our visual range so they just act like mirrors, reflecting all colours. A few have electron transitions that can absorb visible colours...the lack of those in the reflected light is what gives them their colour. 

It turns out the detailed chemistry of this takes you down a horrible rabbit hole of correcting quantum mechanics for the relativistic effects of moving electrons. It gets messy in a hurry.