Full Idea
Prime matter is supposed to be actually nothing and potentially everything or, at any rate, potentially the simplest bodies - earth, water, air and fire.
Gist of Idea
Prime matter is actually nothing and potentially everything (or potentially an element)
Source
Mary Louise Gill (Aristotle on Substance [1989], Ch.1)
Book Reference
Gill,Mary Louise: 'Aristotle on Substance: Paradox of Unity' [Princeton 1989], p.26
A Reaction
The view that the four elements turn out to be prime matter is distinctive of Gill's approach. Prime matter sounds like quark soup in the early universe.