There are four visual clues that tell us that a mole may be dangerous. (ABCD's) A. Asymmetry-Normal moles should appear the same size and shape if divided in half by an imaginary line. B. Border-Moles should have a distinct, smooth margin separating it from normal skin. C. Color-Moles should consist of one evenly distributed color .D. Dimension-A mole should be 6 mm in size or smaller. This is about the size of a pencil eraser. Remember, if an existing mole changes or a new growth appears it is important to see your dermatologist as soon as possible.