Vintage Jewelry lot sterling silver& gp,rings , necklace pendants

Lot of old vintage jewelry finds.3rings 2 silver one stamped "sterling",one stamped gold plate and I can't quite make out what karat it is I can only see the gp mark and something K.Idk if the stones are real diamonds or not.They are pretty though.The rings look pretty old &,have not been cleaned.One is pretty beat up but maybe after its properly cleaned it will be gorgeous.I got them out of a box at an estate sale and am selling them exactly as I found them.Theres a cross and another necklace pendant that has a pretty stone .Again idk if the stones is real diamond or not