Shovel

Shovels are auxiliary tools used to ease the process of collecting dirt, sand, gravel, clay and snow. Shovels are only necessary to collect snowballs from snow; all other blocks for which shovels are useful can be successfully harvested by hand. You may use wood or stone or diamond gem or gold ingot or iron ingots.

Pickaxe

Pickaxes are one of the most commonly used tools in the game, being required to mine all ores and many other types of block. Different qualities of pickaxe are required to successfully harvest certain ores and blocks. For example, diamonds break all ore very fast. You can use gold ingots, diamond (gem), wooden planks, cobblestone and iron ingots to make different pickaxes.

Swords

Swords are weapons used to kill mobs or players (if multiplayer PvP is on) quicker, but are not required to defeat them. They also can remove several blocks faster than using bare hands (such as leaves, wool, glowstone, and Soul Sand), but instead of one use of the Durability Bar, it counts as two uses. Killing larger slimes with a sword will also prevent more slimes from spawning. In The Nether you can find Zombie Pigmen that use Golden Swords, but they do not drop their swords when killed. Because mobs require fewer hits to kill with higher level swords, you will use these swords less, which causes diamond swords to last an extremely long time.
Stone (or better) swords revert minecarts in one hit with no decrease in durability, whereas wooden swords require two hits. You can make a wooden sword (in same pattern but with planks), golden sword (same pattern but with gold ingots), stone sword (same pattern but with cobblestone), iron sword (same pattern but with iron ingots), and diamond sword (same pattern but with diamonds ( gem). )

Gold (Ore)

Gold ore is commonly found by stone blocks deep underground, in a vein of 2-8 blocks (sometimes up to 16 if two veins so happen to spawn together, and down to 1 if the block that was supposed to be gold ore is occupied by a cavern or a dungeon). It shows up at elevations ranging from 0 (the bottom of the map) to 35 (about halfway between sea level and the bottom of the map). Up to 32 it is found in 0.1% of rock, above 32 its abundance falls sharply. It can be mined using an iron or diamond pickaxe. Gold ore can be smelted in a furnace to create gold ingots. Tools made with gold will mine much faster than diamond, however because of its very low durability it is more used for showing off than its value on items/armor. It can also be used to create a watch and a powered rail.

Gold (Block)

Gold blocks (also known as Block of Gold) are blocks for storing gold ingots that do not appear in normally generated maps anywhere.

Gold blocks are available for use in Creative mode and are often used to make shiny buildings or to show "wealth".

Gold is susceptible to destruction from TNT, and only requires approximately 3 seconds to mine successfully.

Gold blocks can be crafted by placing 9 gold ingots in a crafting grid. The gold blocks could then be crafted back into 9 ingots again, making them more useful as "storage units" rather than building units. Golden blocks can be used to make Golden Apples.

Gold (Ingot)

Gold is primarily used to craft clocks, powered rails and for decorative blocks or equipment (tools and armor).

Gold equipment is typically impractical as it has extremely low durability, and can only mine stone, cobblestone, coal and slabs. However, gold tools are the fastest at digging of all tools, and as such may be useful if one is in a hurry and has plenty of gold.

Obtained: smelting of gold ore or craft from gold block.

Creates: sword, armor, tool, gold block, clock, golden apple, powered rail.

Diamond (Ore)

Diamond ore is generally considered to be the most valuable and elusive block in the game. It can be found in a vein of 1-8 blocks (with larger concentrations obviously being more rare). Diamond shows up at elevations ranging from 1 to 19 blocks above the bottom of the map (for comparison, sea level is around 64 blocks above the bottom of the map). Below elevation 18, it occurs in roughly 0.08% of rock. This means that you must check 867 blocks below elevation 18 to have a 50% chance of finding at least one diamond ore. This roughly calculates a little bit above 5 diamonds per chunk. It can be mined for a diamond gem using an iron or diamond pickaxe. The diamond gems can be used right away in a Crafting Table to craft diamond tools, weapons and armor, which are currently the most durable in the game. These, along with coal, flint, Lapis Lazuli, and redstone ore, do not require any smelting and can be used immediately. Diamond blocks can be crafted by placing nine diamond gems together in a 3x3 square using the workbench.
Diamond ore cannot be found or placed in Classic as of version 0.30 and it drops 1 Diamond (Gem) in Indev, Infdev, Alpha and Beta.