| Rather than the singular of qualia (which is quale), qualium is best thought of as the single element in the phenomenologist's periodic table.
Qualia, in philosophy, is a term used to refer to our sensory impressions as they are presented to us: the "raw stuff of experience". Its validity is often disputed, for example on the grounds that when I see a tree, I'm looking at a tree, not at some sensory impression.
However, in phenomenology we can 'bracket' (ie. discard) tricky questions about physical vs. mental, instead identifying all investigable items with elements, or relations between elements, in the 'phenomenal field' - the various possibilities available in experience.
Physical objects and their causal properties might then be thought of as sets of possible experiences - somewhat in this vein, Sartre talks about objectual series.
Thus what we normally take for granted as the ultimate constituents of reality, electrons and atoms and so forth, might be thought of as just patterns of, or relationships between, various 'measuring experiences' (a view oddly in line with orthodoxy about quantum mechanics!) Such objects present us with almost pathological objectual series, being no more than inferences from various calculations and instrument readings.
So when asked to name the ultimate constituents of reality, a phenomenologist might claim instead that "it's all made out of qualium!" | 
