Engineering Geology

• Mineralogy - This is the study on the chemistry and crystal structure and physical properties of mineral constituents inside rocks.
• A mineral is defined to be any naturally occurring inorganic solid that posses an orderly crystalline structure and a definite chemical composition that allows for some variation.
• Precipitation - This is perhaps the most known way of how minerals grow. The mineral starts as an aqueous solution, as time goes by the solution evaporates and as temperatures cool the chemical compounds inside the solution begins to form.
• Crystallization - This happens when magma oozes out of the ground or through volcanic eruption as the exposed lava cools down it also brings raw chemicals and which when they cool and turn into igneous rocks, minerals begin to form as crystals the same is also in effect at evaporating bodies of aqueous solutions.
• Deposition by biological process - Even living creatures can create minerals the best examples of these are cephalopods as they have their outer shell made from calcium carbonate which is a by product of their metabolism.
• Luster - This is the appearance or the quality of light that a mineral reflects or so it appears in the naked eye.
• Metallic - looks shiny like a metal. Usually opaque and gives black or dark colored streak.
• vitreous - looks glassy - examples: clear quartz, tourmaline
• resinous - looks resinous - examples: sphalerite, sulfur
• pearly - iridescent pearl-like - example: apophyllite
• greasy - appears to be covered with a thin layer of oil - example: nepheline
• silky - looks fibrous. - examples - some gypsum, serpentine, malachite
• adamantine - brilliant luster like diamond
• The property of tenacity describes the behavior of a mineral under deformation. It describes the physical reaction of a mineral to externally applied stresses such as crushing, cutting, bending, and striking forces.
• Brittle - Breaks or powders easily.
• Malleable - can be hammered into thin sheets.
• Sectile - can be cut into thin shavings with a knife.
• Ductile - bends easily and does not return to its original shape.
• Flexible – can somewhat bend without breaking, it can return to its original shape if not broken
• Elastic - bends but does return to its original shape
• Hardness has traditionally been defined as the level of difficulty with which a smooth surface of a mineral specimen may be scratched.
• The hardness of a mineral species is dependent upon the strength of the bonds whichcompose its crystal structure.
• Hardness can also be specified using Moh’s scale of Hardness
• Fracture - Minerals having chemical bonds that are equally, or nearly equally, strong in all directions
• Conchoidal – a shell shaped fracture
• Even – flattish shaped fracture
• Uneven - The fracture-surface is rough by reason of minute elevations and depressions -most minerals have an uneven/irregular fracture.
• Hackly - sharp edges and jagged points and depressions
• Splintery - partially separated splinters or fibres
• Cleavage - is a plane of structural weakness along which a mineral is likely to split smoothly.
• The densest mineral is Osmium at 22.59 g/cm3 meaning 22.59 times much heavier than water.
• The least dense is Graphite at 2.26.
• Streak - This is the color of the powder of a mineral when scratched on the surface.
• Aggregate (aggregate): sand, gravel, crushed stone (blasted rock), slag (slag) as concrete(concrete) course used for the construction or artificial or both types often broken in various sizes up to 10cm or broken granular material stack (sand + gravel + natural rock material consisting of crushed stone).
• Gypsum (gypsum); (CaSO4.2H2O-Mohs hardness 2); colorless or white color is converted into plaster losing some of the water at 120 ° C. Plaster is used in indoor and outdoor applications.
• Various clay minerals have been used in mud bricks, bricks, tiles since ancient times.
• The concrete is generally obtained with a mixture of gravel, sand, cement and water depending on the importance and size of the engineering structure to be built, the chemistry of each of these components forming concrete may be primary importance.
• Especially aggregate (sand-gravel) which is added to concrete and constitutes 75-85% by weight of concrete is either naturally extracted from the earth's crust or artificially broken by rock masses.
• Quartz, widely distributed mineral of many varieties that consists primarily of silica, or silicon dioxide (SiO2). Minor impurities such as lithium, sodium, potassium, and titanium may be present.
• Quartz is a gemstone its primary function is the creation of glasses, quartz are almost found everywhere, the gemstone itself is hard to find but the little parts of it are found in any rock as its crystals.