Why do diamonds sparkle?
The atoms in a diamond are tightly packed with electrons — so tightly that light travels at less than half the speed through the crystallized carbon as it does through air. In fact, no other transparent material slows light more than diamond. Jewelers use this unique property to temporarily trap light. They cut and polish diamond in its rough, natural state to produce a gem with smooth sides called facets. Light enters from all sides, and once inside, it bounces off several facets before leaving. The farther the light travels before leaving, the more it separates into the rainbow of colors that make it up. A diamond’s dazzling sparkle, then, results from light’s bouncing travel.
