This is a fresh water pearl necklace with purple beads and gold and silver metal beads.   There are two of these vintage necklaces.  Each necklace measures 19.00 inches long and has a T Bar clasp.

 

The necklaces are vintage, and I cannot see how they are knotted.  They are done in the exact same pattern.

 

Item: Necklace 20754 20755