This is a graduated silver tone metal bead necklace is marked "Korea" and was made before 1945 when Korea split into North and South. 

This necklace measures about 24" long overall, and the beads vary from about 1/4" to 3/4" in diameter.  It shows some wear and some verdigris, otherwise it's in nice vintage condition and looks pretty good for it's age.

Failed test for sterling silver.  Unknown metal content.

c. 1920-1944

Please see pictures for details.