Adamantine is the best, most versatile metal in Dwarf Fortress, but discovering and using it bears great risk. This video will teach you all about adamantine and how you should react to ensure you survive what happens after you find it.
Slaves of Arnok II: Dwarf Fortress, or Dwarf Fortress as it is more commonly known, is one of the most intimidating, challenging, and rewarding PC games in the world. It is totally free to download, available for Windows, Mac, or Linux, and would probably run on a 386. It's a text-based strategy RPG on an epic scale, where you create an empire starting with only seven dwarves and some paltry supplies.
If you're having trouble with it, you're not alone. It's really hard. Click here to watch other how-to videos covering many aspects of the game.