Moles are small areas of skin that are darker than the surrounding skin. They are a collection of cells called melanocytes, which produce the pigment (colour) in your skin. They are also known as melanocytic naevi. Moles are usually a brownish colour, although some may be reddish or black. They are usually circular or oval with a smooth edge. They can be flat or raised, smooth or rough, and some have hair growing out of them. The number of moles people have can increase as they get older. People with fair skin often have more moles than people with darker skin.