Inner Plane - Elemental Planes

The four Elemental Planes are the planes of Air, Fire, Water and Earth.

2nd edition also included the Para-Elemental and Quasi-Elemental Planes. The Para-Elemental Planes are produced where the Elemental Planes come into contact with each other: Smoke (Air and Fire), Ice (Air and Water), Ooze (Earth and Water), and Magma (Fire and Earth). The Quasi-Elemental Planes are produced where the Elemental Planes touch the Energy Planes: At the intersection of the Positive Energy Plane and the planes of Air, Earth, Fire, and Water are Lightning, Minerals, Radiance, and Steam respectively. Around the Negative Energy Planes are Vacuum, Dust, Ash, and Salt.

Note that none of the opposing planes touch one another, as they cancel each other out violently, particularly in the case of Positive and Negative Energy. Thus, Fire and Water do not touch, nor do Air and Earth. There is only one exception to this rule: the Prime Material Plane, which is composed equally of all 6 elements; Earth, Air, Fire, Water, Creation (Positive Energy), and Decay (Negative Energy).