Which of the following optical phenomena is solely responsible for the sparkling brilliance exhibited by a cut diamond?

💡 Solution & Explanation

Diamond exhibits extraordinary brilliance primarily due to multiple instances of total internal reflection caused by its exceptionally high refractive index of approximately 2.42 and a very small critical angle of about 24.4 degrees. Once light enters the diamond at specific facet angles, it undergoes repeated internal reflections before emerging out of particular faces, creating intense sparkle. Simple refraction alone cannot account for concentrated internal trapping and directional light emission. The high refractive index also causes significant dispersion of white light into constituent colors.