Minecraft wiki entry for Trading, associated text: This villager is useful for obtaining emeralds, as you can trade it stone (not cobblestone), especially if you have a stone generator and a Silk Touch pickaxe. Otherwise, you can sell them extra andesite, granite, and diorite that you picked up from a mining session, or buy quartz blocks for a large build. Level them up with the stone trade unless you have a lot of the stone variant to trade away. In Bedrock Edition, you need three masons to trade away each type of stone.