Crystallography and Mineralogy

Crystallography is the experimental science of determining the structure of materials and the three-dimensional arrangement of atoms in molecules. Minerals are classified by key chemical constituents; the two dominant systems are the Dana classification and the Strunz classification. Crystals can be grown under moderate conditions from all 92 naturally occurring elements except helium, and helium can be crystallized at low temperatures by using 25 atmospheres of pressure. A symmetry element is a point of reference about which symmetry operations can take place. In particular, symmetry elements can be identities, mirror planes, axes of rotation (both proper and improper), and centers of inversion. A symmetry element corresponds to a symmetry operation that generates the same representation of an object. Minerals occurring within a rock in small quantities are referred to as “accessory minerals”. Although accessory minerals are present in only small amounts, they may provide valuable insight into the geological history of a rock, and are often used to ascertain the age of a rock. Common accessory minerals are: zircon, monazite, apatite, titanite, tourmaline, pyrite and other opaques. Minerals can be identified by their physical characteristics. The physical properties of minerals are related to their chemical composition and bonding. Some characteristics, such as a mineral’s hardness, are more useful for mineral identification. Color is readily observable and certainly obvious, but it is usually less reliable than other physical properties. Mineralogy, scientific discipline that is concerned with all aspects of minerals, including their physical properties, chemical composition, internal crystal structure, and occurrence and distribution in nature and their origins in terms of the physicochemical conditions of formation. This valuable book offers an account of the wide range of crystallography in various branches of science. This book on minerals has been assembled by a geologist who has taught elementary mineralogy for over a decade.