In Buddhism, gold symbolizes the sun or fire. Alloying gold with other elements is considered sacrilegious as it would dilute its natural brilliance. This is why the gold used for Buddhist sculptures and paintings is always of the purest form - 24k gold. In general, when you see golden Buddhist statues, they were most likely made in Tibetan regions due to the long affinity Tibetans have had with gold in Buddhism.
It does interest me how various colors have become symbolic in Buddhism, but admittedly I can't keep track of it all while I'm traveling. I don't know if I would appreciate it more if I knew the significance of all the colors or not, but I think it's easy enough to appreciate the specific style of Buddhist art and paintings
A decorated wall of the Chimi Lhakhang monastery.