Haumea ("Santa" until a few days ago) is pretty odd as dwarf planet, specialy because it is clearly oval, like a rugby ball. By the 2006 definition of "dwarf planet" it should not have been considered, as one of the requirements is that it would have a spheric shape (hydrostatic equilibrium). But the IAU later lowered their requirements, admitting anything that is bright enough... or something like that. Personally I am not really persuaded it is a good idea, as it allows virtually anything of some size to be considered a dwarf planet.
Well, in any case, what struck me the most from Brown's post is this sentence from the IAU's declaration, re. Haumea's mythology:
"As the goddess of the earth, she represents the element of stone."
Brown also mentions that the object seems to be basically hard rock, with a thin layer of ice covering it (what makes it brighter).
This may be a reference for Astrologers, and I would be tempted to associate it with the sign of Capricorn. Element earth in any case.