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.
Seismic waves and Snellâs law. A wave front is a surface connecting all. points of equal travel time from the. source. Rays are the normals to the. wavefronts, and they point in the. direction of the wave propagation. While the mathematical description of. the wavefronts is rather complex, that. of the rays is simple. For many. applications is it convenient to consider.