The ornamental design for a necklace, as shown and described.
FIG. 1 is a front elevation view of a necklace showing my new design.
FIG. 2 is an enlarged view of the portion highlighted in FIG. 1.
FIG. 3 is a rear elevation view of the necklace of FIG. 1.
FIG. 4 is a left side elevation view of the necklace of FIG. 1.
FIG. 5 is an enlarged view of the portion highlighted in FIG. 4.
FIG. 6 is a right side elevation view of the necklace of FIG. 1.
FIG. 7 is an enlarged view of the portion highlighted in FIG. 6.
FIG. 8 is a top plan view of the necklace of FIG. 1.
FIG. 9 is a bottom plan view of the necklace of FIG. 1.
FIG. 10 is a top perspective view of the necklace of FIG. 1; and,
FIG. 11 is an enlarged view of the portion highlighted in FIG. 10. The logo “BVLGARI” depicted in the figure merely represents written matter surface ornamentation which does not form any part of the claimed design.