"The most common use for obsidian is in creating nether portals for connecting the Overworld with the Nether."
Really, Google!? You favored a Minecraft (video game) fan site over Wikipedia to describe a basic rock?
This is getting as disturbing as Google News, where the top stories themselves may be relevant, but Google generally favors clicks to no-name, third-world sites that do nothing more than rewrite/spin the articles from the original sources, using thesauri and barely-coherent quasi-English.