Introduction to Mineralogy PDF

Introduction to Mineralogy Mineralogy is the study of minerals, their composition, structure, properties, and occurrences. It is a fundamental science that forms the basis of geology, geochemistry, and materials science. Symmetry Elements in Crystallographic Systems 1 Plane of Symmetry 2...

Introduction to Mineralogy Mineralogy is the study of minerals, their composition, structure, properties, and occurrences. It is a fundamental science that forms the basis of geology, geochemistry, and materials science. Symmetry Elements in Crystallographic Systems 1 Plane of Symmetry 2 Axis of Symmetry A plane that divides A line about which a crystal into two a crystal can be mirror images. rotated by a specific angle to produce an identical image. 3 Center of Symmetry 4 Crystallographic Systems A point within a crystal where every Seven systems point has an based on the identical point on symmetry elements the opposite side. present in their crystals. Physical Properties of Minerals The physical characteristics of minerals include traits which are used to identify and describe mineral species. Tenacity Hardness Cleavage Fracture Describes the Resistance to Tendency to How a mineral behavior of a scratching, break along breaks when mineral under measured on specific planes not along a deformation. Mohs hardness of weakness. cleavage plane. scale. The Mohs Hardness Scale is used as a convenient way to help identify minerals. This scale measures a mineral's resistance to scratching— characterizing scratch resistance of minerals through the ability of harder material to scratch softer material. Streak Luster Color The color produced The general Sometimes an by a fine powder of appearance of a extremely diagnostic the mineral when mineral surface to property of a mineral. scratched on a streak reflected light. plate. Specific Gravity Crystal Form A comparison or ratio of the The internal atomic arrangement weight of the mineral to the of a mineral is manifested weight of an equal amount of outwardly by development of water. geometric shapes or crystal characters. Importance of Knowledge of Minerals’ Properties to Civil Engineering It is important for civil engineers to know the properties of minerals especially those that form rocks, to enable them to consider different rocks for any required purpose. For instance, using them: as a foundation rock, as a road metal, as concrete aggregate, as building stones, as floorings, or roofing minerals as decorative material. Rock Forming Minerals Rock-forming minerals are essential to the creation of igneous, sedimentary, and metamorphic rocks. These minerals form as an integral part of the rock-making process. Rocks are assemblies of minerals, each with unique properties and characteristics. Essential minerals constitute more than 50% of a rock's composition. Accessory minerals occur in limited quantities and are typically found as small crystals. Common Rock-Forming Minerals Quartz Augite It's a common mineral found in many A dark-colored mineral often found in rock types. It's made of silicon and igneous rocks. oxygen Biotite Muscovite A black mica mineral, often found in A clear or light-colored mica mineral, igneous and metamorphic rocks. often found in igneous rocks. Feldspar Family Orthoclase KAlSi3O8 Pink, white, or gray Albite NaAlSi3O8 White or gray Anorthite CaAl2Si2O8 White or gray Hornblende, Calcite, and Garnet Calcite A common mineral found in sedimentary rocks like limestone and marble. Hornblende Black or dark green, found in igneous and metamorphic rocks. Garnet A group of minerals known for their beautiful red color, often used in jewelry. Formation of Minerals Minerals are naturally occurring crystalline solid substances. Their atoms are arranged in a consistent, three-dimensional structure, meaning their internal atomic patterns are stable and fixed. Formation from Hot Material A rock is a collection of minerals. Many minerals start out in liquids that are hot enough to melt rocks. Magma cools slowly inside Earth, which gives mineral crystals time to grow large enough to be seen clearly Formation from Solutions Water on Earth, such as the water in the oceans, contains chemical elements mixed into a solution. Various processes can cause these elements to combine to form solid mineral deposits. This process happens in different environments: 1.Minerals from Salt Water 2.Minerals from Hot Underground Water Minerals from Salt Water When water evaporates, it leaves behind a solid precipitate of minerals, as shown in figure below. Water can only hold a certain amount of dissolved minerals and salts. Tufa towers form when calcium-rich spring water at the bottom of Mono Lake bubbles up into the alkaline lake. The tufa towers appear when lake level drops. Minerals from Hot Underground Water Deep underground, magma heats nearby water, which flows through cracks in rocks, picking up dissolved particles. As the water cools or flows into open spaces, it deposits solid minerals in cracks or cavities. These mineral deposits are called veins. Amethyst Minerals can also form in several other way Precipitation from aqueous solution (i.e., from hot water flowing underground, from evaporation of a lake or inland sea, or in some cases, directly from seawater) Precipitation from gaseous emanations (e.g., in volcanic regions) Metamorphism — formation of new minerals directly from the elements within existing minerals under conditions of elevated temperature and pressure. Weathering — during which minerals unstable at Earth’s surface may be altered to other minerals. Organic Formation — formation of minerals within shells (primarily calcite) and teeth and bones (primarily apatite) by organisms (these organically formed minerals are still called minerals because they can also form inorganically). Mineral Formation Fundamental Properties Crystal Structure Chemical Composition The geometric arrangement of the ions The proportions of different chemical (atoms) composing the minerals. elements contained. Coal and Petroleum Origin Coal Petroleum Formed from compressed and altered The word petroleum is derived from petra plant matter in swamps. (rock) and oleum (oil) as it is mined from between the rocks under Earth. Coal Lignite Bituminous Anthracite Petroleum Gasoline Diesel Kerosene Coal and Petroleum Occurrence in India India was a very insignificant producer of petroleum at the time of Independence and remained so till Mumbai High started production on a large scale. In fact, off-shore production did not start till the mid-1970s and the entire production was received from on-shore oil fields.