Tool

Tools
Tools are items used by the player while held to perform actions faster and more efficiently, to gather materials not obtainable by hand, to gain information, or to perform completely new actions. With the exception of the clock and compass, tools do not stack in the inventory. Tools can be repaired, see Item Repair Also, With singleplayer commands, you can also enchant fishing rod and shears, while this is normally impossible.

Item durability
A use is counted only if a player completely breaks apart one block or hits a mob. If a block is partially broken this is not counted as a full use. If a player happens to use a tool that is not suitable for the task at hand (e.g. Using an axe to dig through stone instead of a pickaxe, or fighting a mob with a shovel instead of a sword), will count as two uses rather than one as this is not using the item in hand for its designed use.

Proper use of tools will maximize their durabilities. Assuming a player uses a tool appropriately, the following list shows the maximum durabilities for tools of each material type.


 * Wood - 60 uses
 * Stone - 132 uses
 * Iron - 251 uses
 * Gold - 33 uses
 * Diamond - 1562 uses

Please note though, even though that gold tools have lower durability, they do the work faster.

Diamond tools vs. Gold tools
Gold tools mine blocks the fastest of all tools in the game and have the highest enchantability (making it possible to get Silk Touch with a level 1 enchantment, which is impossible with another tool tier), however they also have the fewest uses (33) and cannot harvest most ores. Most players with the resources opt instead to use diamond tools, which are nearly as fast and have 1562 uses before breaking. Since enchanted tools often gain unbreaking or efficiency, which are of limited use on a golden tool, making and enchanting a gold tool is wasteful, unless the player is trying to get silk touch with the fewest experience levels spent as possible. Fortune is also of little use on a golden pickaxe, which can't mine important ores like iron, gold and diamonds.

Trivia

 * If you switch from a more valuable to a less valuable tool, without releasing the mouse button, just before a block breaks, the time required will be similar to using the former tool, while the mined block will be counted against the latter's durability. This is true for shovels, axes and pickaxes. However, in the case of pickaxes, this only works if the latter can mine this type of block, e.g. for iron and stone pickaxe while mining iron ore it would work, but for diamond and iron pickaxe while mining obsidian it wouldn't. Profitable uses for this (in terms of time saved) are rare.
 * Jens told us around 1:30 in this video that it is going to be possible to upgrade your tools, which is now known as Enchanting.