First of all you need to know that obsidian can be mined with a diamond pickaxe only. Other tools you will be a very long time to pick this block and even destroy it, but mine can't. Obsidian is used to create a portal to the Lower world, to create solid structures and just as expressive tool, because it has interesting texture.
Obsidian occurs in contact of flowing water on lava source (the stationary unit), moreover, it is very rarely found in the wild. The most popular method of mining obsidian is its so-called cultivation with water in the lava lake.
To do this, first you need to find the lava lake. They meet and on the surface, but rarely, and most accumulation can be found at a depth between levels 1 and 10.
Therefore, if around your home you haven't found the lava lake which appeared on the surface, the next time you go to explore the caves, bring a couple of buckets of water or at least one blank. It does not try to carry the water to the Lower world, she's in there evaporates.
Of course, quite often, especially in the canyons in close proximity to each other there are waterfalls and levopoda, but easier to completely fill encountered along the way a small lake of lava with a couple of buckets of water than fumbling with a huge threat spaces. Pour a bucket of water above the lava lake, so it will fill more cells.
Once you have created a number of obsidian to get to its prey. To do this, use the diamond pickaxe, it would be good to enchant it for efficiency to speed up the process. Remember that pickaxe of any other material will not fit, you will only destroy obsidian. Do not stand on the block that is mined! It is possible that beneath lava flows.
Be patient, the usual methacarbamol diamond pickaxe one block of obsidian is extracted ten seconds.
Moving blocks of lava in contact with water turn into cobble or stone.
Be very careful falling into the lava, as a rule, fatal.