Iron Ingot

Iron Ingots are a metal which can be used to craft the fourth tier of armor, and the fourth of tools.

Natural generation
Iron ingots have a chance of appearing in dungeons, strongholds, abandoned mineshafts, villages, and Nether Fortress chests.

Iron golems
Iron Golems drop 3-5 iron ingots upon death.

Zombies
Zombies have a rare chance of dropping an iron ingot.

Trivia

 * Iron Ingots are the most versatile item in the game, being used in 27 crafting recipes. The second most versatile item is Wood Planks with 23 recipes. Technically, if the Nether Reactor Core is counted, Iron Ingots are used in 28 recipes, but the Nether Reactor Core is exclusive to the Pocket Edition, and some crafting recipes that use them are not in the Pocket Edition (such as Iron Doors).

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