The ornamental design for a diamondcut, as shown and described.
FIG. 1 is a front elevational view of the diamond cut showing my new design, the right, rear, and left elevational views being identical to the front elevational view;
FIG. 2 is an elevational view rotated about 45° relative to the view of FIG. 1;
FIG. 3 is a top plan view thereof; and,
FIG. 4 is a bottom plan view thereof.
The broken lines are for exemplary illustrative purposes only and form no part of the claimed design.