Final answer:
Werner's father likely stated that real diamonds are never entirely free of inclusions. Despite these inclusions, diamonds exhibit a characteristic sparkle when illuminated due to the dispersion of white light into its constituent colors, caused by refraction within the diamond's internal facets.
Step-by-step explanation:
Werner's father likely would have said that they are never entirely free of inclusions (b). Real diamonds, while they can be high-quality, often contain microscopic impurities or structural imperfections known as inclusions. However, this does not prevent them from exhibiting remarkable optical properties.
Explanation of Diamond's Sparkle
A high-quality diamond, although clear and colorless, can sparkle with flashes of brilliant color when illuminated by white light due to a process known as dispersion. When white light enters the diamond, it is bent and refracted at different angles. Each wavelength of light is refracted at a slightly different angle, thus separating the light into its constituent colors, much like a prism. The internal facets within the diamond act as many tiny prisms, refracting and reflecting light multiple times, which leads to the extraordinary play of color known as fire. The precise cut of a diamond enhances this effect, creating the characteristic sparkle that diamonds are known for.