The ornamental design for an herbgrinder, as shown and described.
1. Herb grinder
1.1: Perspective
1.2: Front
1.3: Back
1.4: Left
1.5: Right
1.6: Top
1.7: Perspective
1.8: Front
1.9: Back
1.10: Left
1.11: Right
Fig. 1.1is an upper perspective view of an herb grinder of the present design in a closed configuration; Fig. 1.2is a front view thereof; Fig. 1.3is a back view thereof; Fig. 1.4is a left side view thereof; Fig. 1.5is a right side view thereof; Fig. 1.6is a top view thereof; Fig. 1.7is an upper perspective view of an herb grinder of the present design in an open configuration; Fig. 1.8is a front view thereof; Fig. 1.9is a back view thereof; Fig. 1.10is a left side view thereof; Fig. 1.11is a right side view thereof.