Find themes for all colors

[TulkinRB]

We already have some colors with certain "ideas":
black is related to fire (coal and netherite)
blue is magic (lapis and manasteel)

We can try and come up with similar ideas for the rest of the main colors:
Green can be the currency color (emerald and terrasteel which we can use as 2 types of currency)
Maybe copper can be related to liquids? because all fluid things in create are made of copper