Besides building portals, obsidian is primarily useful as an incredibly effective blast-resistant building material. I mentioned earlier that it is some 200 times tougher than any other, excluding the unmineable bedrock, and it is therefore also immune to the attacks of any naturally spawned hostile mob, including exploding creepers. Indeed, the only mob that can break obsidian is the player-created Wither.
Unlike the previous two generators, there is a core problem with automatic obsidian generation: the requirement of lava source blocks. Although it’s possible to build an infinite water source by emptying two buckets of water into the diagonally opposite ends of a 2×2 hole, the same cannot be said for lava. In essence, lava source blocks are a finite resource within any particular chunk, although given the practically infinite size of each Minecraft world (approximately 64,000,000×64,000,000 blocks in surface area), not to mention the enormous lava pools found in the Nether, lava, like any other resource, can be considered essentially infinite.
At this stage there are several ways to obtain obsidian:
Pour water on top of the still lava that fills lava lakes. These are most commonly found below level 10 in the Overworld, and everywhere in the Nether, although they do appear on the surface, especially when you’re playing a customized world using the “Good Luck” preset (see Figure 3.11).
Figure 3.11 Convert a portion of a lava lake into obsidian by pouring water on a non-lava block nearby so that it has the chance to flow over the lava.
- Pour lava into a mold, as shown in Figure 3.12, and then place water on top to form obsidian in the final desired shape. This has the advantage that you don’t need to mine the obsidian with a diamond pickaxe, saving wear on your tools. Figures 3.13 to 3.16 show how to mold a Nether portal frame without mining any obsidian. It doesn’t take long at all and therefore is actually a more efficient construction method than having to tunnel down to layer 12 to find diamonds.
Figure 3.12 Mold obsidian with the placement of surrounding blocks, then pour a bucket of lava into the gap in the middle.
Figure 3.13 You can convert a row of lava with one bucket of water, but building a vertical tower requires a layered approach.
Figure 3.14 Build the frame one layer at a time, placing the lava and then water on top to control the conversion of the blocks. The left side of the frame is ready for the water, whereas the right side shows it already converted.
Figure 3.15 A final spill along a channel at the top completes the frame.
Figure 3.16 The frame is now ready for action and requires just 10 lava source blocks nearby if you leave out the corners.
- Obtain enough obsidian to build a portal (including molding a frame, as described earlier), craft a chest (or a couple of ender chests for even easier content transfers), and pack a diamond pickaxe and a couple of stacks of stone or cobblestone. Place a bed and take a nap at night to reset your spawn point, and then clamber through the portal to travel to the Nether. This creates a portal at your destination, automatically spawning the obsidian blocks required for the frame. Create some protection around the frame using the cobblestone so that you can take the time to knock the obsidian out of the destination frame, piece by piece, without worrying about ghasts flinging fireballs your way. When you’ve finished, place the chest and store everything you have therein—every last skerrick. Then jump into some lava, fall off a cliff, or die in some other convenient way. You’ll respawn next to your bed. Head into the frame again. A new one will appear either at the same place as the original Nether frame or nearby. Take some care before you step out because they can appear over lava, or very close to cliff edges. Then hoist your pickaxe from the chest, take apart the obsidian frame, and repeat. When you have enough, collect everything from the chest and travel back through the frame to the Overworld.