First, you will have to find obsidian or make obsidian naturally in a Minecraft world. This can be done by simply flowing water over a lava pool. To find lava pools, mine your way into deeper caves.

Get some Obsidian Skin Potions instead, and make dealing with lava easy ... Fireblossom x1 Made when Water and Lava collide ...

feature=shared Obsidian Blocks: A minimum of 10 blocks are required. Obsidian is created when water converges with lava ...