Blocks

Blocks are a type of item in Minecraft. They make up the in-game environment, and can be collected and utilized in different ways. Some blocks spawn naturally, such as Dirt or Stone, while others, such as Bricks or Redstone Lamps, must be crafted by the player. Most people would say that wood is one of the most helpful of them.:-)

Certain blocks have special uses, such as Jack-O-Lanterns, Glowstone and Redstone Lamps which can be used to light underwater areas, as they cannot be put out by water (if the Redstone signal going to the redstone lamp is not destroyed).

There are three different transparency levels of blocks. There are completely transparent blocks like air. There are semi-transparent blocks like Glass and Leaves. There are also blocks with 0% transparency, like Wood or Cobblestone. Most blocks that are at least some what transparent will not be able to have torches placed on them.

The face of a block is 16×16 pixels, and each block is proportionately one cubic meter. Most blocks are static, although Water, Lava, Portal, and Fire blocks have a shifting pattern for each side. While the default texture pack's textures are 16x16, there are texture packs with 32x32 or even 64x64 textures. These texture packs often require a mod.

World-generated Blocks
Entries marked with a D require additional data values to entirely define the block in a Minecraft world. Entries marked with an I have a different ID as an inventory item. Entries marked with a B require additional inventory data to fully define the inventory item. Entries marked with a T have tile entities associated with them to store additional data. Items with IDs in red cannot be legitimately obtained by the player in the game; they can only be obtained by "hacking" (Such as using an inventory editor) or, in multiplayer servers, using the /give command. Items available only in Creative mode are in blue. Items only obtainable through the Silk Touch enchantment in survival mode are in green.

The Overworld


Under this paragraph is a list of blocks that currently naturally occur in the overworld.

Naturally Generated
Naturally Generated blocks include blocks that are created through a seed either player generated or generated by a random seed generator.

Naturally Created
Naturally Created means a combination of events that cause a new block to be placed by natural causes, not the Player.



Structures
Same as Naturally Generated, but these blocks are only created with the "Generate Structures" option enabled.

the most pack of blocks is 64

The Nether
To get to the nether, one must obtain at least 10 Obsidian Blocks from the Overworld, a result of the collision of water with still lava. Then fire is added and one can travel to the nether.

Additional Reading
There are currently 153 different types of blocks, including Air,which cannot be built, still Water, still Lava, various types of Wood, various colors of Wool, various types of Pressure Plates, Slabs, Stairs and Double Slabs. See Data Values for the full list.

In a standard randomly generated Map, you can find Air, Stone, Grass, Snow, Dirt, Water, Water Source, Lava, Lava Source, Sand, Sandstone, Gravel, Gold Ore, Iron Ore, Diamond Ore, Redstone Ore, Lapis Lazuli Ore, Clay Block, Coal Ore, Bedrock, Ice, Wood, Birch Wood, Wooden Planks. In Abandoned Mines Pine/Spruce Wood, Leaves, Cactus, Sugar Canes, Vines, Pumpkins, yellow and red Flowers, brown and red Mushrooms, dead and living Shrubs and Tall Grass. In dungeons (added in Seecret Friday Update 2), you can also find Cobblestone, Moss Stone, a Monster Spawner, and Chests, even though cobblestone and chests are usually made by the player. Cobblestone, Wooden Planks, Fences, Pressure Plates, Bookshelves, Crafting Tables, Stairs, Torches, Black Wool, Iron Bars, Lava, Chests and Furnaces may also be found in the randomly generated NPC villages that were added in 1.8, and Stone Brick, Mossy Stone Brick, Cracked Stone Brick, Iron Bars, End Portal Frame, Monster Spawner, Bookshelves, Wooden Planks, Fence, Chest, and Cobweb can be found in the strongholds and abandoned mines also added in 1.8. Obsidian can be found naturally, but it is not part of the random generation; instead it is created when naturally occurring lava source blocks and water come in contact. Cobblestone can also be found naturally, and is formed with the same circumstances as obsidian, except that it is formed when water and moving lava contact. Dungeons are also built of cobblestone in parts.

in other words blocks help you make shelter

In the initial, free version of Survival the player began with 10 TNT blocks and could obtain Dirt, Cobblestone from Stone, Wooden Planks from Wood, Gold Blocks from Gold Ore, Iron Blocks from Iron ore, Stone Slabs from Coal Ore, and white Wool from Sheep.

In Classic mode the player can build with naturally occurring blocks (except for Redstone and Diamond), and can use Bookcase, Sponge, Coloured Wool, Brick, Obsidian and Moss Stone. Operators of servers can also build Bedrock. Some custom servers give the ability to place Grass and (still) Fluids, too.

When playing the current version, the player can craft a variety of blocks not naturally found in maps, including Crafting Tables, Bookshelves, Furnaces and more. Redstone, Diamond, Gold and Lapis Lazuli can be found in the lower areas of maps.

Netherrack, Glowstone, Gravel, Soul Sand, Nether Brick, Nether Brick Fence, Nether Brick Stairs and Nether Wart can be found in The Nether, which the player can only enter by creating a Nether Portal and End Stone and Obsidian can be found in The End, which the player can only enter by inserting Eyes of Ender in all the End Portal Frames. Bedrock, Torches, End Portal and a Dragon Egg are created after beating the Ender Dragon.

The Pocket Edition has 3 additional blocks: The Cyan Flower, Nether reactor core, and glowing obsidian.

Trivia

 * When placing a block in any version of Minecraft with a slightly laggy computer, it may place two blocks when only clicking once, and when you remove one block, it removes them both. This also happens with doors. People with particularly low-end hardware may even experience three blocks being placed or removed with one click of the mouse. A good way of combating this problem is to reduce your view distance to speed up the game.
 * Water is one of the only blocks that you can walk through. The other one is doors.
 * Lava only flows 4 blocks in the Overworld. In the Nether, it can flow 8 blocks, similar to water in the Overworld. If the water block is hacked into your inventory, it can be placed without evaporating and it will flow the same as in the overworld. However, a block update will cause it to evaporate. Lava also flows faster in the Nether.
 * Nether Portal blocks may be considered artificial blocks because players must strike the portal frame with a Flint and Steel to create them.
 * Netherrack, glowstone and Soul Sand are blocks found only in the Nether. They all have helpful uses in the Overworld, such as an infinite light source, traps, and mob spawning(wither).
 * Some blocks must be destroyed by a specific tool in order to be collected, such as Diamonds being mined with an Iron Pickaxe or better.

Gallery
See here