As far as vegetables go, eggplants are very easy to identify. They have a unique shape and color that makes them stand out in the produce aisle. However, the leaves of this plant are not quite as remarkable. Their unexceptional green coloring and conventionally smooth texture prevents many casual observers from distinguishing an eggplant leaf from any other leaf in a garden. But upon closer examination, you will find that eggplant leaves really do have some very distinctive characteristics.
Evaluate the shape of the leaf. The Department of Horticulture at Iowa State University asserts that eggplant leaves should be in the shape of a triangle. However, the triangle will have rounded edges, rather than three sharp points.
Put on your gardening gloves and check the underside of the leaf. According to Dan Drost of Utah State University, you should find prickly thorns if it is indeed an eggplant leaf.
Search the leaves for the presence of beetles and spider mites. A list compiled by the National Science Foundation Center for Integrated Pest Management shows that eggplant leaves are the preferred food of many different types of insects. Unless the plant has been treated with pesticides, you are likely to find a few bugs feeding and holes where other bugs have already eaten.
Use the tape measure to determine the length and width of the leaves. According to John Weaver and William Bruner, the authors of "Root Development of Vegetable Crops," an eggplant leaf on a mature plant can be quite sizable at 8 inches long and 5 inches wide.