| Specification | Description |
| Type | Varieties include English Walnuts, Black Walnuts, and California Walnuts |
| Shape | Round to Oval |
| Diameter | 1 to 1.5 inches (25 to 38 mm) |
| Weight | 12 to 15 grams per whole walnut |
| Color | Light brown to dark brown |
| Shell | Hard, rugged, with a rough surface |
| Shell Thickness | 1 to 2 mm (depending on the variety) |
| Kernel | Light to golden brown, soft, and slightly wrinkled |
| Kernel Size | 0.5 to 1 inch (12 to 25 mm) |
