Minecraft/Diamond Pick and Obsidian

Lava and Obsidian
In the deeper layers of the Overworld (and rarely on the surface) you may come across lava lakes. When lava touches water different things can happen:
 * If lava flows against stationary water, the water will solidify to Stone.
 * If lava flows against running water, the lava will solidify to Cobblestone (this can be used to make infinite cobblestone).
 * If water flows against stationary lava, the lava solidifies to Obsidian.

Lava source blocks cannot be created and must be found in the caves and lava spread from them. Water can be infinitely reproduced by putting two buckets of it at opposite corners of a 2x2 hole in the ground.

Obsidian
Obsidian is a very hard block and can only be successful be mined with a Diamond Pickaxe. Obsidian can use to make Enchantment Tables, Ender Chests and building a Nether Portal. To make an enchantment table, you need a minimum of 14 obsidian (18 if you want your nether portal to have corners), which can usually be obtained from a single lava lake.

(Optional) Ranged Weaponry
You can make a Bow using 3 Sticks and 3 pieces of String. String is a drop form Spiders and can be harvest from Cobwebs. You can equip your Bow as a weapon, but it needs Arrows as ammo. To make an Arrow you need 1 Feather, 1 piece of Flint and 1 Stick, which gives you 4 Arrows. Feathers are drops of Chickens and Flint can be dug out of Gravel.

First use the bow (same button as placing/eating) to draw back the Bow if you have at least 1 Arrow. Hold the button longer to shoot farther and cause more damage. At maximum charge your bow will shake and cause up to 9 damage. Release the button to fire. You can't sprint with a charged Bow.