One 1oz coil will make many necklaces approx 36 coils of  Stainless steel memory wire 0.62mm (0.025) wire. Coil 9.2 to 10.2cm diameter (3.63 to 4.00 inches)

The wire is very hard and springy, but can be worked with pliers. Finish with end caps or make loops with round nosed pliers.  
You may wish to try forming an addition loop in the centre of the wire to add charms.