What does crystal structure refer to?

Crystal structure refers to the regular, repeating internal arrangement of atoms within a material. This arrangement determines many of the physical and chemical properties of the mineral, including its symmetry, cleavage, and overall stability. The specific arrangement of atoms can influence how a gemstone interacts with light, which affects its appearance and optical properties. In contrast, while the shape and external appearance of the gemstone are important, they are not indicative of the internal atomic structure. The external features and the gem's formation process are related to the gem's aesthetic and geological origin but do not define the fundamental crystal structure itself. Understanding crystal structure is essential in the study of mineralogy and gemology, as it provides insight into the classification and identification of various gemstones.