Minecraft wiki entry for Villager, associated text: Using an employed villager allows a player to trade, making offers based on the villager's profession and profession level. All offers involve emeralds as a currency, and items related to the villager's profession. Trading can allow the acquisition of items that would otherwise be difficult or impossible to obtain, such as enchanted books with "treasure" enchantments (e.g. Mending), bottles o' enchanting, or chainmail armor. When a villager gets a new trade, they receive 10 seconds of Regeneration I (totaling to 4 of restoration), which emits pink particles. The villager also emits green particles suggesting contentment.