Hi.  I have three sets of pearls that have been given to me.  The first set on the bottom was my grandmother's - she was born in 1899 so probably from the early to mid 1900s.  I assume they are costume. There are no markings on the clasp.  There is some wear at the connections, but overall they are in ok shape.  This is a 14" choker with 53 pearls.  The other two necklaces were given to me by my mother-in-law.  Supposedly they were her mother-in-laws: an Italian woman who came to the United States in 1900.  The middle necklace is in horrible condition.  It is 24" long with 95 pearls.  They are dull, dirty and flaking a lot.  The top necklace is a pretty champagne golden color.  15" strand of 94 graduated pearls, there is no clasp.  They appear to be in good condition.  I plan to restring this necklace for sentimental reasons and because I like the color! Can anyone tell if these are real pearls and suggest an appropriate clasp.  I can send more picture, just let me know what you want to see. Thanks so much for any thoughts or comments!