This ultra high-clarity, laboratory-grade glass prism is optimized to demonstrate one of the most fundamental behaviors of light: refraction.

Refraction is the bending of light as it travels through different materials. Because light moves more slowly in glass than in air, the beam changes direction at the boundary. Each wavelength is slowed by a slightly different amount, so colors spread apart into a rainbow: red, with its longer wavelength, bends the least, while violet bends the most. The result is a crisp spectrum—the hidden makeup of white light.

Laboratory-grade optics like this are manufactured to be exceptionally pure and bubble-free, with minimal internal stress. Ordinary glass contains impurities and uneven structure that scatter light, but optical glass is carefully melted, filtered, and cooled so that its refractive index is consistent throughout. The result is sharp, vivid color separation without haze or distortion, perfect for optics labs to study the physics of light or create controlled beams for experiments.

For the best effect, shine a narrow beam of sunlight or a focused flashlight through one face at about 60° in a dim room, projecting a brilliant spectrum onto a white surface.