What you have are cultured pearls, not gem quality pearls. These are objects made of shell inserted into the oyster and left long enough for one or more layers of pearl nacre to be coated on them by an oyster. Since these are from the "pick your pearl" oysters it is probably one thin layer of pearl nacre rather than several, as there would be on higher quality cultured pearls.
So this layer is going to be very prone to damage, chipping, or coming completely off.
You cannot bake them. You do not want to use anything other than jeweler's cement made for pearls to attach them to anything, or you will discolor, dissolve, or otherwise mar that very thin layer of pearl nacre. Super Glue is NOT safe on pearls. Something like Hypo Cement, for instance.
http://www.amazon.com/G-S-Hypo-Cement-J ... B000YQDX86Hypo Cement is brittle, however, and if there is likely to be any stress you might want to try a safe-for-pearls super-glue like epoxy that jewelers use, called VIGOR
http://www.amazon.com/Vigor-Jewelry-Dry ... super+glueBest of all is the long-cure version of Araldite, if you expect there to be some stress on the pearl.
http://www.amazon.com/Araldite-2011-Slo ... dite+epoxy