What is a mole? What types of skin moles are there? Not all moles are created equal. Here’s a quick guide to mole types and what they mean for our skin. Read how to identify them and keep your skin healthy. Moles, also called nevi, are common (most people have between 10 and 40 moles) round or oval growths that may be tan, brown, black, or pink. Moles happen when melanocytes grow in clusters in the skin, and the spots may be flat or raised. Get information on melanoma (skin cancer) signs, diagnosis, treatment, prognosis, and symptoms. Learn about staging, early detection, treatment side effects, prevention, metastatic melanoma, and see pictures of this form of skin cancer.