What are fingernails made of? Why do they appear pink?

A lifeless, translucent outgrowth of skin, the fingernail appears pink because it lies over a bed of tissues that is rich in blood. It does not, however, grow from this bed. It originates in a matrix of specialised skin cells that lie below the whitish half moon, that is visible at its base. Unlike the cells of the translucent plate, those in the matrix are very much alive, constantly growing and pushing the cells ahead of them toward the fingertip. As they emerge from the matrix, the cells become filled with a hard protein called keratin. Unlike other skin cells, these highly keratinised cells are not slought off when they die. Instead, they become compact into the structure that we call a fingernail. The nail grows continuously. If it is removed without damage to the matrix cells, a new nail will grow in its place.