The roundness of individual grains can tell us much about a…

The roundness of individual grains can tell us much about a rock’s depositional history. The image below shows relative levels of rounding that clasts can display. What is the primary difference between the depositional histories of the grain labeled A and the one labeled B? Click to view larger image.

The image below shows the atomic structure of a graphite cry…

The image below shows the atomic structure of a graphite crystal. The hexagons are made by strong covalent bonds, while the sheets are held together by much weaker Van Der Waal forces. Based on this information and the shape of the structure, how many planes of cleavage could graphite be expected to have?Click to view larger image.