This piece is a favorite! Its a mixed link paper clip chain. A classic with a twist. (note the paper clip link is 3/4" in length). The chain is made up with a paper clip link, elongated oval link and round links. The pattern is consistent all the way around. The clasp is a nice size claw clasp.
 
Metal = 14k yellow gold chain
Length = 7"
Thickness =  4.5 to 6 mm