The ornamental design for a jewelryfastener, as shown.
FIG. 1 is a perspective view of a jewelry fastener configured in accordance with an embodiment of the present invention;
FIG. 2 is a top plan view of the jewelry fastener of FIG. 1;
FIG. 3 is a front elevational view of the jewelry fastener of FIG. 1;
FIG. 4 is a rear elevational view of the jewelry fastener of FIG. 1;
FIG. 5 is a side elevational view of the jewelry fastener of FIG. 1; and,
FIG. 6 is a front perspective view of the jewelry fastener of FIG. 1, wherein end portions of the jewelry fastener are separated to illustrate interior sections of the end portions.