Final answer:
Diamonds sparkle with brilliant colors due to total internal reflection and the large index of refraction that cause light to undergo multiple reflections inside the diamond. The colors emerge from dispersion, which splits white light. Prominent companies like DeBeers control much of the diamond industry, influencing global production and distribution.
Step-by-step explanation:
A high-quality diamond may be quite clear and colorless, effectively transmitting all visible wavelengths with minimal absorption. When such a diamond is illuminated by white light, it can sparkle with flashes of brilliant color. The phenomenon behind this sparkle is total internal reflection, which occurs due to the diamond's large index of refraction. A diamond has a critical angle of only 24.4°, making it difficult for light to exit once it enters. The facets are designed to ensure light undergoes multiple internal reflections before exiting, resulting in a concentrated, bright sparkle.
Despite their generally colorless appearance, the brilliant colors seen are the consequence of dispersion. Dispersion causes white light to split into its constituent colors, creating the colorful sparkle. Moreover, some diamonds manifest inherent colors due to structural defects or the incorporation of foreign materials such as graphite.
DeBeers, a prominent company in the diamond industry, controls a significant portion of global diamond production with operations in various countries and a vast distribution network for rough diamonds.