Lecture 1 GOVERNMENT ENGINEERING COLLEGE, PATAN TOPICS:- MINERALOGY BRANCH- CIVIL

Lecture 1 Mineralogy A ‘Mineral’ defined as a natural, inorganic, homogeneous, solid substance having a definite chemical composition and regular atomic structure. Mineralogy is that branch of geology which deals with various aspects related to minerals like mode of formation, composition, occurrence, association, properties, uses, etc.

Lecture 1 Civil engineering importance of rock – forming minerals The civil engineers need to know the properties of rock precisely to enable them to consider different rocks for various purposes such as foundation rocks, road mental, concrete aggregates, building stones, flooring material, roofing material, etc, Thus properties of civil engineering importance such as strength, durability, hardness, appearance, etc. of rocks can be assessed only with the knowledge of the minerals that forms rocks.

Lecture 1 Minerals and their properties Every mineral has a certain set of properties, which will be characteristic of that mineral. Mineral has some properties like as under. 1.Physical properties 2.Chemical properties 3.Optical properties 4.X-ray analysis

Lecture 1 Physical properties Minerals have some various physical properties as under. 1.Form (Habit):- the form represents the common mode of occurrence of a mineral. 2.Color :- the color of a mineral is due to absorption of certain wave lengths of white light by atoms making up the crystal. The remaining wave length of white light that are not absorbed give rise to the color seen by the observer.

Lecture 1 3.Streak :- the color of the mineral powder is called streak. 4.Luster :- luster is the nature of shining on the surface of the mineral. It is a measure of the reflectivity of light of the mineral surface. 5.Clearage :-it is defined as the tendency of a crystallized mineral to break along certain definite directions, yielding more or less smooth, plane surface. 6.Fracture :-the fracture of a mineral may be defined as the appearance of the randomly broken surface.

Lecture 1 7. Hardness :-hardness is defined as the resistance of a mineral to abrasion, or scratching. It is on of the most important diagnostic properties of mineral. 8.Specific gravity:- it is the ratio of the weight of a mineral to the weight of an equal volume of water. Transparency:- it is the capability to pass light through mineral. If an object can be seen fully and easily through a mineral, it may be called as transparent.

Lecture Tenacity :- the behaviour of a mineral towards the forces that tend to break, bend, cut or crush it, is described by the tenacity. 11.Fluorescence :- when mineral exposed in sunlight or ultraviolet light, produce a color quite different from their own. This property of mineral is called fluorescence. 12.Phosphorescence:- mineral glow and emit light when they are placed in ultraviolet light of certain other electrical radiation. This property of minera is called phosphorescence.

Lecture 1 PETROLOGY Is a branch of geology, which deals with study of rocks (Petro=rock, Logos=study) ROCKS IGNEOUS -most abundant -primary rocks -source is magma or lava SEDIMENTARY -thin veneer above the Sail and Sigma in Oceanic and Continental Crusts -secondary rocks METAMORPHIC -proportion is similar to that of Igneous rocks -change of forms of Ig. And Sed. Due to Temperature, Pressure and Chemical Fluids

Lecture 1 Rocks Rocks may defined as aggregates of mineral. Some rocks, such as quartz and marble, contain grains of one mineral only but most are composed of a variety of different minerals.

Lecture 1 Classification of rocks The rocks are classified in various ways based on different principal such as physical classification, chemical classification, geological classification. Geological classification of rocks: 1.Igneous rocks 2.Sedimentary rocks 3.Metamorphic rocks

Lecture 1 1.Igneous rocks Igneous rocks are formed by cooling and solidification of magma. Magma term is applied when the melt is underground. When it reaches the earth’s surface and flows over it, is called lava. The rocks formed by the consolidation of magma are said to be primary rocks. These rocks are the oldest ones formed on earth’s crust.

Lecture 1 Typical characters Presence of crystalline mineral and interlocking texture. Formed from a high temperature rock melt. They are usually massive, un stratified, un fossiliferous. The volcanic igneous rocks are always extremely fine grained. Examples: granite, basalt, gabbros, senate, andesine, etc.

Lecture 1 2.Sedimentary rocks This rocks are formed by consolidation and cementation of the sediments deposited under water. Sedimentary are the products of weathering. This rocks are also called layered rocks because weathered sediments are transported and deposited on the oceanic floor in the form of layers.

Lecture 1 Typical characters Lamination or bedding or stratification. Cross bedding or current bedding or torrential bedding. Prescience of cementing material. Occurrence of fossils. Occurrence of tracks and trails. Occurrence of mud cracks, rain prints etc. Porous, concretionary, nodular structures Ripple marks Examples: sandstone, limestone, shale conglomerate, dolomite, etc.

Lecture 1 3.Metamorphic rocks This rocks are formed when the pre- existing rocks have been changed in texture and composition by increased temperature and pressure. The older rocks may be either sedimentary, igneous or other metamorphic rocks. During metamorphism re crystallization takes place essentially in the solid state and new mineral and new textures are produced.

Lecture 1 Typical characters Some mineral like staurolite, andalusite, kainite and garnets, this are the products of metamorphism are only found in metamorphic rocks. Some structures and textures like lineation, foliation, schistosity and salty cleavage are metamorphic rooks. Metamorphic rocks are composed of coarse grained mineral.

Lecture 1 Importance of civil engineering on petrology Petrology is very important from civil engineering, because this provides a proper concept and logical basis for interpreting physical properties of rocks. The study of texture, structure, mineral composition, chemical composition, gives all necessary details regarding the strength, durability, color, appearance, workability, etc.

Lecture 1 Thank you……