Quartz Core is a graphics rendering and animation framework used in Apple operating systems, such as iOS and macOS. It provides developers with tools to create smooth and efficient graphics, enabling high-quality visual effects and animations in applications. The framework is built on top of the Core Graphics API and utilizes hardware acceleration to improve performance. This allows for faster rendering of 2D graphics and complex animations, making it easier for developers to create visually appealing user interfaces and engaging experiences for users.