CRUZITA is misspelled. It should be Crucita. The rule says that all "Z" in words, when made into the diminutive form, should be transformed into "C"
i.e. Brazo (arm) = bracito (little arm) Hence,
Cruz = Crucita.
Z an C in such cases are pronounced the same way: the equivalent to English phonetic "TH" as in "thunder" or "think"
Hope it is of your interest,
Magia