The ornamental design for a decorativeelement for a watch dial, as shown and described.
FIG. 1 is a top view of a decorative element for a watch dial showing my new design;
FIG. 2 is a front view of the invention;
FIG. 3 is a back view of the invention;
FIG. 4 is a side view of the invention;
FIG. 5 is another side view of the invention, showing the side opposite that shown in FIG. 4; and,
FIG. 6 is a top perspective view thereof.
The portion of the part of watch that is shown in broken lines in the drawings is for illustrative purposes only and does not form part of the claimed design.