Iron Ore

Iron ore is a mineral block which may be found underground. It is the most common mineral which may be used to make tools and armor.

Iron ore requires a stone, iron, or diamond pickaxe to successfully mine. It must then be smelted in a furnace to make an iron ingot; iron ingots can be used to make medium quality tools, armor, buckets, Flint and Steel and shears. A full list of craftable items can be found at Crafting.

Most players prefer using iron tools, since iron is far more common than Diamond and more durable than Stone. Iron ore is often used in player traps as it can be mined and replaced in its raw form.

Natural Occurrence
Iron occurs only at or below sea level (layers 1-64). It is found in approximately 0.72% of stone from rows 2-61. On average, there are about 77 iron ores per chunk. Due to being extremely common, iron veins are frequently seen at the boundaries of any hollow space such as caves and lava lakes, but they are no more common there than in any other volume of stone.

Veins can vary in size, though most common size is 2x2x2. Iron can come in veins of one. Each block in the vein which otherwise would be stone has a random chance of being iron ore instead. (Therefore, it is good practice to check around a located ore block for more ore, as ore blocks may be only diagonally adjacent rather than face-to-face.) If the vein intersects a cave or other structure, part of it may be replaced with empty air.

Iron also has a tendency to appear near coal ores - it isn't at all rare for a vein of coal to lead right to one of iron. It would be wise to mine coal in search of iron.

History
Iron ore was introduced in Classic 0.0.14a. Iron in Classic spawns in huge veins, sometimes big enough to protrude into 3 caverns, and could be as big as 167 ores.

In Survival Test, breaking iron ore gave the player 1 - 3 blocks of iron when mined. In a later version(which?), it began dropping iron ingots.

In Indev(January 29, 2010) before the furnace was added, The Player smelted ore by dropping ore blocks onto fire.

As of Indev(Febuary 1, 2010), iron ore requires a stone, iron, or diamond pickaxe to successfully extract.

As of 1.2.1, iron is a renewable resource because Iron Golems will drop 3-5 iron ingots upon death and zombies have a rare chance of dropping iron ingots upon death as well.

Trivia

 * In third person view, all ores being held by the player such as Diamond Ore, Gold Ore, or Redstone Ore, seem to look like the texture is reversed, like TNT.
 * In Minecraft 1.3, smelting iron ore, along with other ores, blocks and items, gives you experience orbs when taking the item out of the furnace, allowing for a different way to get enchantments. One stack of iron ore will give roughly 2 lvl.

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