Most freshwater pearls do not have a bead nucleus...however their are very large strands can have a bead - look at the Forums about 'Edison' pearls . But the pearls you are using, judging from your photos, do not have a bead.
At the top of the Forum page there is a section called Pearl Education which is really helpful without overloading you with information It is confusing when you first get into 'pearls' .
At the top of the Forum page there is a section called Pearl Education which is really helpful without overloading you with information It is confusing when you first get into 'pearls' .