THE SCIENCE BEHIND THE SPARKLE
Perhaps the most magical feature of a diamond is its sparkle – the enthralling way it reflects light when illuminated. But it’s not really magic, just a combination of the diamond cutter’s art and the science of optics. From the latter point of view, the two key processes are reflection and refraction. The first of these simply refers to the way light hitting one of a diamond’s facets – either from outside or internally – can be reflected, as if by a mirror. As for refraction, that’s most commonly encountered in the context of lenses, where it refers to the way a lens bends light. But the same thing happens when light travels between any two transparent substances, including air and diamond. The skill in diamond cutting is to produce facets at just the right angles so that the combined effects of reflection and refraction send as much light as possible towards the viewer.