Twinning
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joTwinning occurs when two crystals of the same substance grow together in a crystallographically controlled manner. There are several types of twinning defined by the twinning element, which can be a twin plane, twin axis, or twin center. Twinning is common across different crystal systems, with typical twinning elements being low index crystal planes or directions. Characteristic twinning patterns can be used to identify minerals under the microscope.
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Solid State sysem4 feb21
Lecture notes on Solid State as per the revised syllabus of S.Y.B.Sc class laid down by the University of Mumbai which is in force from June 2017.
Structure of matter(miller indices).pptx
Miller indices were introduced in 1839 as a method to uniquely identify crystallographic planes and directions in a crystal structure. The Miller indices (hkl) are a set of integers that represent the inverse of the intercepts of a plane with the crystallographic axes. There are rules for determining the Miller indices based on these intercepts, such as always reducing fractions to lowest terms. Miller indices allow the orientation of different crystal planes and directions to be precisely defined and compared.
Geo
Continental-continental convergence occurs when two continental plates collide and push against each other, forming large mountain ranges such as the Himalayas. When sedimentary layers between the plates are crumpled and folded, fold mountains are created, with anticlines where the rocks fold upward and synclines where they fold downward. Folds can be symmetrical, asymmetrical, isoclinal, overturned, or recumbent, depending on the orientation and steepness of the axial plane and limbs. Examples of fold mountain ranges include the Himalayas, Alps, Andes, Rockies, and Urals.
Symmetry
Symmetry refers to the orderly and proportionate arrangement of parts that produces a balanced form. It is important in biology, mathematics, and mineralogy. In biology, symmetry can be bilateral around a central axis or radial around a central point. In geometry, symmetry involves transformations that produce identical or mirror images of shapes. In mineralogy, crystal structures are classified based on their symmetry properties. Symmetry in physics refers to systems that remain unchanged under transformations like mirroring or time reversal, and relates to conservation laws.
Crystal stmmetry
Crystal symmetry is defined by repeated patterns of atoms in a crystal structure. There are different types of symmetry operations including planes of symmetry, axes of symmetry, and centers of symmetry. Planes of symmetry divide the crystal into mirror images, axes of symmetry involve rotational symmetry, and centers of symmetry involve equidistance from a point. The six main crystal systems are defined by their unique combinations of symmetry elements and are classified from highest to lowest symmetry as isometric, tetragonal, orthorhombic, hexagonal, monoclinic, and triclinic. Miller indices and Weiss parameters are used to describe the orientation of crystal planes.
B.Sc. I Year Physical Chemistry_Unit III_A- Solid State
B.Sc. I Year Physical Chemistry_Unit III_A- Solid StateDepartment of Biochemistry, Veer Bahadur Singh Purvanchal Univarsity, Jaunpur
The document discusses key concepts regarding solid states and crystallography. It defines crystalline and amorphous solids, and describes the ordered crystal lattice structure of crystalline solids. It then outlines three fundamental laws of crystallography: 1) the law of constancy of interfacial angles, 2) Hauy's law of rationality of indices, and 3) the law of constancy of symmetry. The document also discusses techniques for determining crystal structures, including Bragg's law of diffraction and X-ray diffraction methods like the Laue method and powder method.Introduction to Crystallography
Nature of crystals; crystalline and amorphous materials; polycrystalline materials; a brief introduction to Crystal systems.
X ray crystallography
X-ray crystallography uses X-rays to determine the three-dimensional structure of molecules. Symmetry elements like centers of symmetry and planes of symmetry describe the repeating patterns in a crystal lattice. Bragg's law relates the wavelength of X-rays to the diffraction pattern produced when X-rays interact with the regular array of atoms in a crystal and bounce off the lattice planes.
Study of deform rocks, folds and its types
This document summarizes a presentation on the study of deformed rocks and geological folds. It defines key terms like anticline and syncline folds, describes different types of folds like symmetrical, asymmetrical, and recumbent folds. It explains how rocks deform under stress, the different types of strain (elastic, ductile, and brittle), and how geological structures relate to stress and strength. Methods for identifying folds in the field are also summarized, including directly observing folds and measuring the attitude of hinges and axial planes.
Similar to Twinning (20)
Basics of crystallography, crystal systems, classes and different forms
Basics of crystallography, crystal systems, classes and different forms
B.Sc. I Year Physical Chemistry_Unit III_A- Solid State
B.Sc. I Year Physical Chemistry_Unit III_A- Solid State
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Amphiboles
The amphiboles are a group of chain silicate minerals with some substitution of F and Cl for OH. They have a general formula of (W,X,Y)7-8(Z4O10)2(OH)2 where W represents large cations like Ca and Na, X represents smaller cations like Mg and Fe2+, Y represents Fe3+, Ti, and Al, and Z represents Si and Al. Amphiboles have elongate prismatic crystals and two prismatic cleavages that meet at 124 degrees, whereas pyroxenes have squat prisms and cleavages that meet at 88 degrees. Common amphiboles include hornblende, tremolite, actinolite
Amphiboles
The amphiboles are a group of chain silicate minerals with some substitution of F and Cl for OH. They have a general formula of (W,X,Y)7-8(Z4O10)2(OH)2 where W represents large cations like Ca and Na, X represents smaller cations like Mg and Fe2+, Y represents Fe3+, Ti, and Al, and Z represents Si and Al. Amphiboles have elongate prismatic crystals and two prismatic cleavages that meet at 124 degrees, whereas pyroxenes have squat prisms and cleavages that meet at 88 degrees. Common amphiboles include hornblende, tremolite, actinolite
Amphiboles
The amphiboles are a group of chain silicate minerals with some substitution of F and Cl for OH. They have a general formula of (W,X,Y)7-8(Z4O10)2(OH)2 where W represents large cations like Ca and Na, X represents smaller cations like Mg and Fe2+, Y represents Fe3+, Ti, and Al, and Z represents Si and Al. Amphiboles have elongate prismatic crystals and two prismatic cleavages that meet at 124 degrees, whereas pyroxenes have squat prisms and cleavages that meet at 88 degrees. Common amphiboles include hornblende, tremolite, actinolite
Amphiboles
The amphiboles are a group of chain silicate minerals with some substitution of F and Cl for OH. They have a general formula of (W,X,Y)7-8(Z4O10)2(OH)2 where W represents large cations like Ca and Na, X represents smaller cations like Mg and Fe2+, Y represents Fe3+, Ti, and Al, and Z represents Si and Al. Amphiboles are distinguished from pyroxenes by having a different Si:O ratio and containing essential OH groups in their structure. Common amphiboles include hornblende, tremolite, actinolite, anthophyllite, cummingtonite, grunerite,
Amphiboles
The amphiboles are a group of chain silicate minerals with some substitution of F and Cl for OH. They have a general formula of (W,X,Y)7-8(Z4O10)2(OH)2 where W represents large cations like Ca and Na, X represents smaller cations like Mg and Fe2+, Y represents Fe3+, Ti, and Al, and Z represents Si and Al. Amphiboles have elongate prismatic crystals and two prismatic cleavages that meet at 124 degrees, whereas pyroxenes have squat prisms and cleavages that meet at 88 degrees. Common amphiboles include hornblende, tremolite, actinolite
Nature and behaviour of light
Light can vibrate in one plane (be polarized) through selective absorption or reflection. When light passes from one medium to another of different density, some of the light will be reflected and some will pass through but be bent and slowed down (refracted). The angle of reflection equals the angle of incidence, while the angle of refraction depends on the change in velocity.
The index of refraction and relief of a mineral are used to identify it. Index of refraction is a measure of how light slows down when passing into a mineral and is related to its crystal structure. Relief refers to the difference in index of refraction between a mineral and its surroundings, and is used to estimate the index of ref
Copy of nature and behaviour of light
Light can vibrate in one plane (be polarized) through selective absorption or reflection. When light passes from one medium to another of different density, some of the light will be reflected and some will pass through but be bent and slowed down (refracted). The angle of reflection equals the angle of incidence, while the angle of refraction depends on the change in velocity.
The index of refraction and relief of minerals can be used to identify them. Index of refraction refers to how much light is refracted when passing from one substance to another. It varies based on crystallographic orientation in anisotropic minerals. Relief and birefringence are properties related to the index of refraction.
Space lattices
Crystals have basic building blocks called unit cells that are arranged in a periodic pattern described by a lattice. The unit cells contain motif groups of atoms associated with each lattice point. There are 14 possible types of space lattices belonging to 7 crystal systems characterized by distinct unit cell shapes and symmetries. The crystal structure is defined by the space lattice and the motif or basis group of atoms.
Rhombohedron
The document summarizes different crystallographic forms in the trigonal and tetragonal crystal systems. It describes rhombohedrons as solids bounded by six rhomb-shaped faces, and scalenohedrons as solids bounded by 8 or 12 scalene triangle faces. It also discusses sphenoids as four-faced solids resembling tetrahedrons but with isosceles triangle faces, and tetragonal scalenohedrons bounded by eight similar scalene triangles.
Presentation1
Crystals are defined as a 3D periodic arrangement of atoms in space, known as a lattice, with a motif or basis of atoms associated with each lattice point. A lattice is a 3D periodic arrangement of points without the atoms. Together, the lattice and motif define the crystal structure. There are 14 possible lattice arrangements, known as Bravais lattices, which are categorized into 7 crystal systems based on their symmetry properties. The lattice and basis completely specify the crystal structure.
Forms of crystals.
This document describes several crystal classes and forms. It discusses:
1) The pyritahedral class which includes forms like the pyritahedron and diploid bounded by 12 or 24 faces respectively.
2) The tetrahedral class including forms like the tetrahedron, deltoid dodecahedron, trigonal tristetrahedron, and hextetrahedron bounded by 4, 12, 12, and 24 faces.
3) Prism forms in the tetragonal, hexagonal, and orthorhombic crystal systems defined by their faces being parallel to the c-axis including first, second, and third order prisms.
Crystal structure
This document discusses crystal structures, including periodic arrays of atoms, fundamental lattice types, crystal planes indexed using Miller indices, and imaging atomic structures. It covers common lattice types like simple cubic, body-centered cubic, and face-centered cubic. Simple crystal structures presented include sodium chloride, cesium chloride, diamond, and zinc sulfide. Non-ideal crystal structures can involve random stacking or polytypism with long repeat units along stacking axes.
Crystal forms.
The document describes several common crystal forms including the cube, octahedron, and rhomb-dodecahedron. It provides details on the number of faces, their shapes, and how they intersect the crystallographic axes for each crystal form. Some common crystal forms mentioned are the cube, octahedron, rhomb-dodecahedron, tetrahexahedron, trapezohedron, trisoctahedron, hexoctahedron, pyritohedron, diploid, and tetrahedron.
Nature and behaviour of light
Light can vibrate in one plane (be polarized) through selective absorption or reflection. When light passes from one medium to another of different density, some of the light will be reflected and some will pass through but be bent and slowed down (refracted). The angle of reflection equals the angle of incidence, while the angle of refraction depends on the change in velocity. Minerals can be characterized by their index of refraction (n), which is a measure of how much light is bent when passing into the mineral. It determines properties like relief and birefringence. Some minerals like calcite have the property of double refraction, where a single ray of light enters and splits into two rays.
Feldspar
Feldspar is the most abundant mineral group found in igneous and metamorphic rocks. It has a continuous three-dimensional network structure of silicon-oxygen and aluminum-oxygen tetrahedra with positively charged sodium, potassium, calcium, or barium ions situated between. The two most common feldspar types are orthoclase (potassium feldspar) and plagioclase (sodium-calcium feldspar). Plagioclase can form as a solid solution or break down into intergrowths of sodic and potassic lamellae called perthites. Feldspars are found in a wide range of igneous and metamorphic rocks depending on their
Silica
Quartz is one of the most abundant minerals and is composed of silicon dioxide (SiO2). It has a complex crystal structure and exists in several polymorphs including alpha-quartz, beta-quartz, tridymite, cristobalite, coesite, and stishovite. The stability of these polymorphs depends on temperature and pressure conditions. Cryptocrystalline varieties of quartz include chalcedony, agate, jasper, chert, and flint. Macrocrystalline varieties include rock crystal, milky quartz, amethyst, rose quartz, citrine, and smoky quartz.
Pyroxene
The document discusses the pyroxene group of minerals. Pyroxenes have a single chain crystal structure and are ionosilicates containing elements like calcium, sodium, magnesium, iron, and aluminum. They can be orthorhombic or monoclinic in crystal form. The general chemical formula of pyroxenes is (W,X,Y)2Z2O6, where W, X, Y, and Z can be elements like calcium, magnesium, iron, aluminum, sodium, lithium, silicon, and more. Some common pyroxenes mentioned include enstatite, hypersthene, diopside, hedenbergite, augite, and pigeonite.
Mica group
This document summarizes several types of phyllosilicate minerals in the mica group, including their chemical formulas, crystal structures, and common occurrences. Muscovite, biotite, and phlogopite are some of the most common micas. They have layered structures and perfect basal cleavage. Muscovite is widely used in electrical and insulation applications due to its properties. The document also describes lepidolite and its identification by lithium content and lilac color.
Feldspathoids
Feldspathoids are silicate minerals that are chemically similar to feldspars but deficient in silica. They form in place of feldspars when magma lacks sufficient silica. Common feldspathoids include leucite, nepheline, sodalite, cancrinite, and analcime. Some feldspathoids contain unusual anions like chloride, carbonate, sulfate, or sulfide. Leucite is characteristic of potassium-rich volcanic rocks. Nepheline occurs in both plutonic and volcanic alkaline, silica-poor rocks. Sodalite forms blue veinlets and masses and is found in nepheline syenites and phonolites.
Forms of crystals.
This document describes several crystal classes and forms. It discusses:
1) The pyritahedral class which includes forms like the pyritohedron bounded by 12 faces and the diploid bounded by 24 faces.
2) The tetrahedral class including the tetrahedron bounded by 4 faces and the deltoid dodecahedron bounded by 12 quadrilateral faces.
3) Different types of prisms in the tetragonal, hexagonal, and orthorhombic crystal systems defined by their orientation relative to the crystal axes and number of faces.
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Twinning
- 1. TWINNING