Minecraft wiki entry for Emerald, associated text: Emerald ore drops one emerald when mined using an iron or better pickaxe. If the pickaxe is enchanted with Fortune, it may drop an extra emerald per level of Fortune, up to a maximum of 4 emeralds with Fortune III. If the ore is mined using a pickaxe enchanted with Silk Touch, it drops itself in ore form instead of an emerald.