What does a high refractive index indicate about a material?

A high refractive index indeed indicates that a material bends light more than materials with lower refractive indices. The refractive index is a measure of how much light slows down as it passes through a material compared to its speed in a vacuum. When light enters a medium with a high refractive index, the change in speed causes the light to change direction more significantly. This bending of light is also known as refraction.

For example, materials like diamond have a high refractive index, resulting in a pronounced bending effect, which is why diamonds sparkle so dramatically when cut properly. The extent to which light bends when passing from one medium into another is a critical aspect of optics and plays a significant role in various applications, including lens design and optical instruments.