Copper is related to “time” while Amethyst is related to “sight”.

In Minecraft some items have a sort of theme to them. For example, blaze powder is always related to alchemy while lapis is related to enchanting, and gold seems to be related to “speed” (powered rails and clocks). To give these items more potential for uses, Amethyst and Copper should be related to “sight” and “time” respectively, since Amethyst is used to craft spyglasses and tinted glass (sight-related items) and Copper ages, so maybe it could be used to craft items relating to time (maybe change the clock recipe to copper?)