The ornamental design for a finial for curtainrod, substantially as shown and described.
FIG. 1 is an isometric view showing the top and side of my invention;
FIG. 2 is an elevation view showing the side of my invention;
FIG. 3 is an elevation view showing the top of my invention; and,
FIG. 4 is an elevation view showing the bottom of my invention.
The broken line showing of a curtain rod in FIGS. 1 and 3 is included for the purpose of illustrating environment only and forms no part of the claimed design. The broken lines in FIG. 4 define the boundary of the claimed design and form no part of the claimed design.