This is one of the old types of prisms. Spectrometer prism is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. This is probably the oldest spectrometer know to man. In spectrometer prism the free spectral range covers the whole region of normal dispersion of the prism material. A spectrometer prism is used in spectroscopy for producing spectral lines and measuring their wavelengths and intensities.