Streams of invisible power run beneath the earth, occasionally crossing and collecting in a single spot like river flowing into a lake. Such rare collection points are called earth nodes.
An earth node’s power isn’t visible to the naked eye, but such points are often eerily beautiful or bizarre. A giant geode or a teardrop–shaped, smooth-sided cavern might hold an earth node, as might any other wondrous subterranean shape. Such a sight isn’t always present, though, and the node’s power doesn’t respect physical boundaries. Some nodes even extend to the surface world.
The most common nodes are fairly small and weak. The exact size of a node and its field of power varies from as wide as half a mile to about 30 feet across. Powerful nodes are rare and can radiate their influence over a greater distance, but the strength of the effect doesn’t always correlate to a wider field.
A few nodes have concentrations of active Spellplague. These horrifying places are essentially small, underground plaguelands called plaguecaves.