The majority of golf balls use a core that is made from synthetic rubber. The rubber core may be mixed with metal or plasticized materials. However, the core of a golf ball can be filled with various other materials, which vary in price and quality.
Common metals that are used inside of golf balls include titanium or tungsten. Some three-piece golf balls use a liquid core, such as the salt water and corn syrup blend used in Titleist balls. Golf balls used on the driving range are typically made of surlyn, which comprises both the interior and exterior of the ball.