Seleite

Seleite is the rare Underdark crystal used in the creation of Warforged. Seleite is a clear crystal until it is infused with magic, after which it takes a number of colours depending on the magic it retains. This mineral is mined deep under the overworld territory of Legierungsland. It is also sacred to some Duergar populations who openly wage war on miners and those who would try to take it to the surface. Likewise, Duergar have been known to capture and dismantle Warforged to obtain their precious Seleite core.