Modified Post on 2/8/09: uploaded corrected image, updated format.
I wanted a new way of looking at elements for my fantasy setting that would incorporate all the elements I was interested in while also showing their relationships. Hence the graphic above.
I've been playing around with a way of classifying some of the classical elements alongside other elemental forces that seem significant to me. I've looked at sources like The Magician's Companion and Real Energy, among others. Still, the traditional western and Chinese elemental categories weren't quite satisfying to me.
The four classical elements are presented in their classic wheel formation. In between each neighboring primary elements on the wheel is a secondary element formed from a mixture of the two elements bordering it.
For example, Rain (which includes all precipitation) sits between Air and Water because it shares properties of both. Wood shares properties of Water and Earth, Metal shares properties of Earth and Fire, and Electricity (understood here as electromagnetism) shares properties of Fire and Air.
At the center of everything, interwoven with it on a quantum level, is the immaterial element of Spirit.
I feel pretty satisfied with this as a model organizing the basic "real world" forms of Forces and Matter that can be easily observed and distinguished from other types, with Spirit representing the essence that is perceived only indirectly by most.
I also think I can fit it into my fantasy setting very cleanly and that it will help me visualize and define the forms of elemental magic available and their interrelationships.