Calcite, the most common form of natural calcium carbonate (CaCO3), a widely distributed mineral known for the beautiful development and great variety of its crystals.
A wavefront is a surface over which an optical wave has a constant phase. For example, a wavefront could be the surface over which the wave has a maximum (the crest of a water wave, for example) or a minimum (the trough of the same wave) value. The shape of a wavefront is usually determined by the geometry of the source.
Definition of 'shock wave'. shock wave also shockwave. A shock wave is an area of very high pressure moving through the air, earth, or water. It is caused by an explosion or an earthquake, or by an object travelling faster than sound. The shock waves yesterday were felt from Las Vegas to San Diego.