What are the main uses of equilateral prisms?
Spectroscopy experiments: decomposition of composite light (e.g. white light) into monochromatic light for spectral analysis.
Laser system: to adjust the direction of the optical path or as a resonant cavity element.
Imaging system: inverted image or deflection of the light path, such as telescopes, microscopes in the steering prism.
Teaching demonstration: demonstrate basic optical phenomena such as refraction, total reflection and dispersion.

Comparison of materials for equilateral prism
Characteristic	SF11	BK7	Fused Silica
Refractive Index (nd)	1.784	1.517	1.458
Abbe Number (vd)	25.68 (high dispersion)	64.2 (low dispersion)	67.8 (extremely low dispersion)
UV Transmittance	Relatively Poor  (>350 nm)	Middling (>300 nm)	Excellent (>190 nm)
Cost	Relatively High	Low	Middling