The ornamental design for a finial, as shown and described.
FIG. 1 is a front elevational view of a finial showing my new design;
FIG. 2 is a rear elevational view thereof;
FIG. 3 is a right side elevational view thereof (left side is a mirror image);
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a perspective view of my new design in use; and,
FIG. 7 is a rear perspective view of my new design in use.
The lighter broken lines in the figures depict a portion of the finial that is not part of the claimed design. The darker broken lines in FIGS. 6 and 7 depict environment that is not part of the claimed design