Aeronautics (from the ancient Greek words á½°Î®Ï ÄÄr, which means air, and Î½Î±ÏÏÎ¹ÎºÎ® nautikÄ which means navigation, i.e. navigation into the air) is the science or art involved with the study, design, and manufacturing of air flight capable machines, and the techniques of operating aircraft and rockets within the atmosphere.
Diamond-like substitutes, including cubic zirconia, a crystalline compound synthesized from the elements ziconium and oxygen, attempt to mimic this light-dispersing property, though they fall short of diamond's brilliance and unrivaled hardness.
Diamonds have been found in rocks that are thought to have been subducted and then returned to the surface. These types of rocks are very rare and no known commercial diamond deposits have been developed within them. The diamonds found in these types of deposits have been very small and not suitable for commercial use.