The ornamental design for the infinity head for jewelry, as shown and described.
FIG. 1 is a front perspective view of an infinity head for jewelry showing my new design;
FIG. 2 is a front view thereof.
FIG. 3 is a rear view thereof.
FIG. 4 is a left view thereof.
FIG. 5 is a right view thereof.
FIG. 6 is a top view thereof.
FIG. 7 is a bottom view thereof.
FIG. 8 is an enlarged top perspective view thereof; and,
FIG. 9 is an enlarged front elevational view thereof.
The broken lines that connect the solid contour lines along the sides of the jewelry head illustrate the bounds of the claim. The remaining broken lines shown in the drawings represent environment. None of the broken lines form a part of the claimed design.