A solid object is in the states of matter characterized by resistance to deformation and changes of volume. At the microscopic scale, a solid has these properties : The atoms or molecules that compose the solid are packed closely together. These constituent elements have fixed positions in space relative to each other. This accounts for the solid's rigidity. In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. A crystal structure is composed of… (More on Solids)