The ornamental design for a piece of jewelry, as shown and described.
FIG. 1 is a side view of a plurality of pieces of jewelry having block letters, shown in phantom, with stones, shown in phantom, fixedly secured to the bottom thereof, with the pieces of jewelry strung together with a necklace chain, shown in phantom;
FIG. 2 is a front view of one embodiment of the piece of jewelry;
FIG. 3 is a back view of the piece of jewelry shown in FIG. 2;
FIG. 4 is a side view of the piece of jewelry shown in FIG. 2;
FIG. 5 is a top view of the piece of jewelry shown in FIG. 2; and,
FIG. 6 is bottom view of the piece of jewelry shown in FIG. 2.
The broken line showing of gemstones and block letters is for illustrative purposes only and forms no part of the claimed design.