Breaking

Digging is one of the most fundamental activities in Minecraft, performed by holding the left mouse button while the cursor is over a block. Digging is used to create passages and tunnels, to clear away unwanted blocks, and is also the primary way of acquiring blocks for future placement or crafting.

Basics of digging
Digging is accomplished simply by holding the left mouse button while the cursor is over a block. If you are within 4 blocks of the target, you will begin swinging you hand, making a repetitive "thump" noise as you hit the block, and cracks will begin to appear. (When you are in range, the block will also by marked with a wireframe cube outline, showing you the current target.) After the cracks completely cover the block, it will break, and depending on the type of block and the tool you are wielding you might harvest it for resources.

Although many blocks can be harvested with your bare hands, the harder ones require the use of a tool. In particular, to get resources from stone or metal-type blocks, you will need to use a Pickaxe. For harder blocks like Iron Ore or Obsidian, not just any pickaxe will do; you need one made from sufficiently hard materials. You can also use Shovels and Axes to speed up digging of dirt and wood-type blocks, although they are not required to get the resource drop. The downside is that tools have durability, and so they eventually wear out.

You will continue to dig as long as the mouse button is held down, although there is a slight pause of 0.25 seconds between destroying one block and beginning on the one behind it. You can move freely while digging, and you can even dig while jumping or swimming! (Although there is a speed penalty for the latter two, see below.) This makes it easy to dig long tunnels or to clear away a large volume of material.

You lose your digging progress if the target block changes while digging, so it is best to target the middle of a block's face. Progress is also reset whenever the mouse button is released. This can be used to your advantage because of a quirk in the handling of the "cooldown" between blocks: the 0.25 second cooldown is reset when you release the mouse. Thus, with proper timing you can "click mine," increasing your overall digging throughput. (The "thump" noise is helpful for gauging this: it plays exactly 5 times per second, starting as soon as you click. For example, mining Stone with an Iron Pickaxe takes 0.4 seconds, so there are two thumps plus a little extra time before the block breaks.) It used to be possible to "switch mine" by switching targets right as the block broke to accomplish the same thing, but that no longer resets the cooldown.

Digging speed
The speed at which you dig is controlled by two factors: The block you are breaking, and the item you are currently wielding. Every block has a hardness, which determines the base amount of time to break that block if you hit it with your bare hands. The first adjustment to this is based on whether you can harvest the block with your current tool. If you cannot, then the base time is multiplied by 3.33.

Assuming that you can harvest the block, the next check is whether your tool helps speed digging for this block. By and large, Pickaxes speed up (and are required for) mining stone, Axes help chop wood, and Shovels dig dirt faster. There are some notable exceptions, though: Pickaxes don't speed up mining Redstone Ore or Obsidian, which is why they take so long to mine. Similarly, Shovels don't help with Soul Sand.

If your tool helps, then it increases digging speed by a constant multiplier, given in the following table:

Lastly, digging can be slowed if you are not on the ground. There is a 5x penalty (digging takes five times as long) if you are not standing on the ground while digging. There is also a 5x penalty to digging while in water. If you are swimming, (underwater and not walking on the bottom,) then the two combine for a whopping 25x penalty, making it very difficult to dig even with tools. However, if you cannot harvest with your current tool then only the original 3.33x penalty applies, and none of the other adjustments are made. This means that it is faster to punch stone while swimming than to use an Iron Pickaxe! Sadly, there's no way to apply this to Dirt, since everything can harvest it.

Blocks by hardness
The following table shows the time it takes to break each type of block. Values marked with an asterisk and a red background indicate that it cannot be harvested by that quality of tool. (Note that some blocks, like Ice, don't drop anything even when they are "harvested.") If there is no tool that helps speed up mining the block, the row will have a grey background.