What it is:
Zinc Oxide, a white powder, is the oxide of zinc.
What it does:
Zinc Oxide is used as a sunscreen agent due to its ability to block the entire UV range. It does this by creating a shield on the skin that reflects light away from it.
Zinc Oxide, because of its white colour, is also used in colour cosmetics to create a wide variety of shades.
Zinc Oxide is generally considered to be safe. But, because of its white colour, it can leave a white cast on the skin.