Amethysts and Copper need to provide players with more advantages

Gold is used in brewing, rails, foods, while iron is used in redstone, transport, golems and progression; these things have a direct impact on players and provide an immediate advantage, but neither amethysts nor copper really do this yet. Tinted glass is cool, spyglasses are cool, etc, but however many ways you can use them for builds, there's no real motivation for us to gather them until they can be used to actively shape gameplay.

Copper and amethysts need to play a bigger role in progression; either for potion brewing by offering new effects, for combat progression by affecting enchantments or introducing new risk/reward type armors, or for building progression, by granting players new, better ways to build structures (new scaffolding?), craft (new workstation?) or transport items or entities around.