Eww. Hideous.
Isn't the actual value of this pearl, well, nil? There's nothing inherently valuable about pearls, it's about their beauty, and this thing isn't beautiful. As a novelty or museum attraction, maybe it has value, but it's not something to kill for!
The actual value is whatever price people are willing to pay for it, and apparently, there are people willing to squander millions on it. Cubic zirconia is just as pretty as a diamond... but people get diamonds because they are a status symbol, and not necessarily for their beauty... and the perl is a pretty big status symbol.