Minecraft wiki entry for Trading, associated text: Villagers have five career levels that can be increased by trading with them. Each villager starts at the "novice" level. A villager's level can be seen in the trading menu. The badge they wear can also be identified: stone for a novice, iron for an apprentice, gold for a journeyman, emerald for expert, and diamond for master. Trading until the villager's trading bar gets full unlocks the next level of trades. When a player trades with a villager, both the villager and the player gain experience. All villager trades reward the player with 3–6 experience, or 8–11 experience if the villager is willing to breed. Trading with a wandering trader also rewards the player some experience, although the trader does not have experience levels to gain. A villager levels up when its experience bar becomes full and gains up to two new trades, along with keeping their old ones. Additionally, a villager receives a Regeneration effect, and becomes surrounded by purple and green particles for ten seconds.