This document provides an introduction to crystallography. It defines crystallography as the study of crystals, which are solid substances with regular internal structures bounded by flat planar faces. The document outlines the key elements of crystals, including crystallographic axes, axial angles, crystal systems, symmetry elements, Miller indices, and habits. It also briefly discusses atomic structure, chemical bonding, and polymorphism as relevant concepts in crystallography.
this is a case chapter for class 12 as it was not available on the net however this ppt u won't be able download ...if you personally want it pls contact me on ritik.tatia@gmail.com .......
The objectives of this course in iron ore Resources and iron industry are:
i) acquainting students (majors and non-majors) with the basic tools necessary for studying iron ore deposits and processes,
ii) different processes for phosphorus removal from iron ore
iii) beneficiation processes of iron ore deposits.
iv) different processes and techniques that used to enrichment low-grade iron ore resources
v) understanding the different ironwork processes and technology,
vi) understanding the different types of iron ore products,
vii) prominent routes for steelmaking
viii) understanding the relationship between the distribution of iron ore and scrap, as well as steelmarkets,
ix) steel industry in Egypt , and
x) gaining some knowledge of the global iron ore as well as environmental problems associated with the extraction and utilization of iron ore resources.
There are plenty of hard-to-beneficiate iron ores and high-grade tailings in India and all over the world; As the volume of high-grade iron ores declines.
Minerals phase transformation by hydrogen reduction (MPTH) can efficiently revitalize hard-to-beneficiate iron ore resources and tailings, turning the waste into profitable products. It may also improve the concentrate quality comparing to that from the previous method. From the economic and environmental aspects, MPTH is the most effective method to recover iron oxides.
The clean minerals phase transformation by hydrogen reduction (MPTH) was proposed.
Industrial utilization of limonite/goethite, limonite-hematite, sulfur-bearing refractory iron ore was achieved, where Sulfur-bearing minerals decomposed or formed sulfate after oxidation roasting.
Sulfur content of iron ore concentrate was significantly reduced to 0.038 %.
Improving utilization efficiency of refractory iron ore resources is a common theme for the sustainable development of the world’s steel and iron industry.
Magnetization Roasting is considered as an effective and typical method for the beneficiation of refractory iron ores.
After magnetization roasting, the weakly magnetic iron minerals, including hematite, limonite and siderite, are selectively reduced or oxidized to ferromagnetic magnetite, which is relatively easier to enrich by Magnetic Separation after liberation pretreatments.
The Primary Magnetization Roasting Methods include: Shaft Furnace Roasting, Rotary Kiln Roasting, Fluidized Bed Roasting, and Microwave assisted roasting. The developments in magnetization roasting of difficult to treat iron ores, including: Shaft Furnace Roasting, Rotary Kiln Roasting, Fluidized Bed Roasting, and Microwave Assisted Roasting in the Past Decade.
Shaft Furnace Roasting is gradually eliminated due to its high energy consumption and low industrial processing capacity, and the primary problem for rotary kiln roasting is the kiln coating which affects the yield of iron resource and its industrial application.
Fluidized Bed Roasting and Microwave assisted roasting are considered as the most effective and promising methods.
Suspension (Fluidized) Magnetization Roasting is recognized as the most effective and promising technology due to its high reaction efficiency, low energy consumption and large processing capacity. Moreover, an industrial production line with a throughput of 1.65 million t/a for beneficiation of a specularite ore has been built.
Microwave Assisted Roasting is a potential alternative technology for magnetizing iron ores. However, it is currently limited to laboratory research and has no industrial application. Forwarding microwave assisted magnetization roasting methods into industrial applications needs long way and time to achieve.
Furthermore, using biomass, H2 or siderite as a reducing agent in the magnetic reduction roasting of iron ores is a beneficial way to reduce carbon emissions, which can be called clean and green magnetization roasting technology.
In the future, technical research on clean and green magnetization roasting should be strengthened. Maybe microwave magnetization roasting using biomass/H2/siderite as reductant can be further studied for a more effective and greener magnetization of iron ores.
WORLD RESOURCES IRON DEPOSITS
Iron Ore Pellets Market Industry Trends
Scope and Market Size
Market Analysis and Insights
DRI Production in Plants Using Merchant Iron Ore
Outlook for DR grade pellet supply‐demand out to 2030
DRI and the pathway to carbon‐neutral steelmaking
Supply‐side challenges for the steel & iron ore industries
scrap is the main raw material, is growing in the structure of global steelmaking capacities; SCARP/ RECYCLING IRON ; EAF steel production method in the world; Scrap for Stock; A Global Scrap Shortage;Availability of Ferrous Scrap Resources; EGYPT IRON SCRAP IMPORTS.
The iron ore production has significantly expanded in recent years, owing to increasing steel demands in developing countries.
However, the content of iron in ore deposits has deteriorated and low-grade iron ore has been processed.
The fine ores resulting from the concentration process must be agglomerated for use in iron and steelmaking.
Bentonite is the most used binder due to favorable mechanical and metallurgical pellet properties, but it contains impurities especially silica and alumina.
Better quality wet, dry, preheated, and fired pellets can be produced with combined binders, such as organic and inorganic salts, when compared with bentonite-bonded pellets.
While organic binders provide sufficient wet and dry pellet strengths, inorganic salts provide the required preheated and fired pellet strengths.
The industrial development program of any country, by and large, is based on its natural resources.
Currently the majority of the world’s steel is produced through either one of the two main routes: i) the integrated Blast Furnace – Basic Oxygen Furnace (BF – BOF) route or ii) the Direct Reduced Iron - Electric Arc Furnace (DRI - EAF) route.
Depleting resources of coking coal, the world over, is posing a threat to the conventional (Blast Furnace [Bf]–Basic Oxygen Furnace [BOF]) route of iron and steelmaking.
During the last four decades, a new route of ironmaking has rapidly developed for Direct Reduction (DR) of iron ore to metallic iron by using noncoking coal/natural gas.
This product is known as Direct Reduced Iron (DRI) or Sponge Iron.
Processes that produce iron by reduction of iron ore (in solid state) below the melting point are generally classified as DR processes.
Based on the types of reductant used, DR processes can be broadly classified into two groups: (1) coal-based DR process and (2) gas-based DR process.
Details of DR processes, reoxidation, storage, transportation, and application of DRI are discussed in this presentation.
This presentation reviews the different DR processes used to produce Direct Reduced Iron (DRI), providing an analysis on the quality requirements of iron-bearing ores for use in these processes. The presentation also discusses the environmental sustainability of such processes. DR processes reduce iron ore in its solid state by the use of either natural gas or coal as reducing agents, and they have a comparative advantage of low capital costs, low emissions and production flexibility over the BF process.
Currently the majority of the world’s steel is produced through either one of the two main routes: i) the integrated Blast Furnace – Basic Oxygen Furnace (BF – BOF) route or ii) the Direct Reduced Iron - Electric Arc Furnace (DRI - EAF) route.
In the former, the blast furnace uses iron ore, scrap metal, coke and pulverized coal as raw materials to produce hot metal for conversion in the BOF. Although it is still the prevalent process, blast furnace hot metal production has declined over the years due to diminishing quality of metallurgical coke, low supply of scrap metal and environmental problems associated with the process. These factors have contributed to the development of alternative technologies of ironmaking, of which Direct Reduction (DR) processes are expected to emerge as preferred alternatives in the future.
This presentation reviews the different DR processes used to produce Direct Reduced Iron (DRI), providing an analysis on the quality requirements of iron-bearing ores for use in these processes. The presentation also discusses the environmental sustainability of such processes. DR processes reduce iron ore in its solid state by the use of either natural gas or coal as reducing agents, and they have a comparative advantage of low capital costs, low emissions and production flexibility over the BF process.
Ironmaking represents the first step in steelmaking.
The iron and steel industry is the most energy-intensive and capital-intensive manufacturing sector in the world (Strezov, 2006).
Steelmaking processes depend on different forms of iron as primary feed material. Traditionally, the main sources of iron for making steel were Blast Furnace hot metal and recycled steel in the form of scrap.
The Blast Furnace (BF) has remained the workhorse of worldwide virgin iron production (i.e., hot metal) for more than 200 years. Over the years, BFs have evolved into highly efficient chemical reactors, capable of providing stable operation with a wide range of feed materials.
However, operation of modern efficient BFs normally involves sintering and coke making and their associated environmental problems.
More than 90% of iron is currently produced via the BF process, while the rest is coming from Direct Reduction (DR) processes, Mini Blast Furnaces (MBFs), Corex, Finex, Ausmelt, etc. Additionally, the severe shortage of good-quality metallurgical coal has remained an additional constraint all over the world. In view of this, there is an increasing awareness that the BF route needs to be supplemented with alternative ironmaking processes that are more environment friendly and less dependent on metallurgical coal.
Because of the rapid depletion of easily processed iron ores, the utilization of refractory ores has attracted increasing attention .
There several billion tonnes iron deposits, and most are refractory ores, which are difficult to process by conventional methods because of the low iron grade, fine grain size and complex mineralogy.
The beneficiation of low-grade iron ores to meet the growing demand for iron and steel is an important research topic.
At present, magnetization roasting followed by magnetic separation is one of the most effective technologies for the beneficiation of refractory iron ores.
However, certain ores do not qualify to be treated in physical separation processes, and hence, alternative strategies are being looked into for upgrading their iron content.
Reduction roasting has many advantages over the physical beneficiation process, such as enhanced iron recovery and processing of complex and poorly liberated iron ores.
The objective of this presentation is to compile and amalgamate the crucial information regarding the beneficiation of low-grade iron ores using carbothermic reduction followed by magnetic separation, which is a promising technique to treat iron ores with complex mineralogy and liberation issues.
Reduction roasting studies done for different types low-grade iron ores including oolitic iron ores, banded iron ores, iron ore slimes and tailings, and industrial wastes have been discussed.
Reduction roasting followed by magnetic separation is a promising method to recover the iron values from low-grade iron ores.
The process involves the reduction of the goethite and hematite phases to magnetite, which can subsequently be recovered using a low-intensity magnetic separation unit.
The large-scale technological advancements in reduction roasting and the possibilities of the application of alternative reductants as substitutes for coal have also been highlighted.
This presentation aims at insight light on the occurrence of phosphorus in iron ores from the mines around the world.
The presentation extends to the phosphorus removal processes of this mineral to meet the specifications of the steel industry.
Phosphorus is a contaminant that can be hard to remove, especially when one does not know its mode of occurrence in the ores.
Phosphorus can be removed from iron ore by very different routes of treatment. The genesis of the reserve, the mineralogy, the cost and sustainability define the technology to be applied.
The presentations surveyed cite removal by physical processes (flotation and selective agglomeration), chemical (leaching), thermal and bioleaching processes.
Removal results of above 90% and less than 0.05% residual phosphorus are noticed, which is the maximum value required in most of the products generated in the processing of iron ore.
Chinese studies show that the direct reduction roasting of high phosphorus oolitic hematite followed by magnetic separation is reality technical solutions to improve the recovery of metallic iron and dephosphorization rate.
For ores with widespread phosphorus in the iron matrix and low release, thermal or mixed processes are closer to reality technical solutions. Due to their higher operating costs, it will be necessary to rethink the processes of sintering and pelletizing, such that these operations also become phosphorus removal steps.
With the exhaustive processing of the known reserves of hematite from Iron Ore Quadrangle (Minas Gerais-Brazil), there will be no shortage of granules in the not too distant future. THEREFORE, THERE IS AN EXPECTATION THAT THE ORE MINED WILL HAVE HIGHER LEVELS OF PHOSPHORUS.
Overview of IRON TYPES: Pig Iron, Direct Reduced Iron (DRI), Hot Briquetted Iron (HBI), Cold Briquetted Iron (CBI) and Cold Briquetted Iron and Carbon (CBIC) Specifications .
Comparison of Pig Iron and DRI
Properties; Manufacturing Process; Uses; Largest producers and markets
Iron ore mining plays a critical role in supplying the raw material necessary for steel production, supporting various industries and economic development worldwide.
From the extraction of iron ore to its processing and eventual export, each stage of the mining process requires careful planning, technological advancements, and environmental considerations.
By adopting sustainable mining practices and mitigating environmental impacts, the future of iron ore mining can be aligned with the principles of responsible resource utilization and environmental stewardship
The Egyptian steel sector is the second largest steel market in the Middle East and North Africa region in terms of production and third largest in terms of consumption.
Egypt was the third-ranked producer of Direct-Reduced Iron (DRI) in the Middle east and North Africa region after Iran and Saudi Arabia and accounted for 5.4% of the world’s total output
The Egyptian steel industry represents one of the cornerstones of Egypt’s economic growth and development, due to its linkages to almost all other industries that stimulate economic expansion, such as construction, housing, infrastructure, consumer goods and automotive. All these industries rely heavily on steel industry and so, the importance and development of the steel sector is significant for the progress of the Egyptian economy in general.
The Egyptian market has many companies that produce different steel products.
Geological consultant, working in a range of roles from project development/feasibility study programs and advanced exploration roles. Contracts in a variety of global locations including Egypt, Saudi Arab, and the Middle East. Commodities including Gold, base metal sulfide, Gossan/Supergene, heavy mineral sands, clay/kaolin, Silica Sand, and iron ore.
Exploration in Deep Weathering Profiles, Supergene, R-mode factor analysis; Multi-element association geochemistry; Assessment of Au-Zn potentiality in Gossan; Rodruin-Egypt
Mineral Processing: Crusher and Crushing; Secondary and Tertiary Crushing Circuits; Types of Crusher; Types of Crushing; Types of Jaw Crushers; Impact Crusher; Types of Cone Crushers; Ball Mill; BEST STONE MANUFACTURERS; Local Quality and High quality ; International and Country/Hand made
Classification Equipment
Introduction; Chemical composition of garnet; Structure; Classification; Physical properties; Optical properties; Occurrences; Gem variety; and Uses
Garnet group of minerals is one of the important group of minerals.
Since they are found in wide variety of colours, they are also used as gemstones.
Garnet group of minerals are also abrasives and thus have various industrial applications.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
2. CONTENTSCrystallography:
Why we study Crystallography?
Definition
External characteristics of crystals
• Elements of crystals
Crystal elements
Crystal symmetry
Crystal systems
Crystal classes
Axial ratios-crystal parameters and Miller indices
Methods of Crystal Drawing
Crystal habit and forms
• General Outlines of the crystal systems
Cubic (Isometric) System
Tetragonal System
Orthorhombic System
Hexagonal System
Trigonal System
Monoclinic System
Triclinic System
3. Atomic structure
Central region called the nucleus
Consists of protons (+ charges) and neutrons
(- charges)
Electrons
Negatively charged particles that surround
the nucleus
Located in discrete energy levels called
shells
4.
5.
6.
7.
8. Chemical bonding
Formation of a compound by combining
two or more elements
Ionic bonding
Atoms gain or lose outermost (valence)
electrons to form ions
Ionic compounds consist of an orderly
arrangement of oppositely charged ions
9.
10. Covalent bonding
Atoms share electrons to achieve
electrical neutrality
Generally stronger than ionic bonds
Both ionic and covalent bonds typically
occur in the same compound
12. Polymorphs
Minerals with the same composition but
different crystalline structures
Examples include diamond and graphite
Phase change = one polymorph changing
into another
13.
14.
15. Crystal form
External expression of a mineral’s
internal structure
Often interrupted due to competition for
space and rapid loss of heat
16. Why we study Crystallography?
It is useful for the identification of minerals. The
later are chemical substances formed under natural
conditions and have crystal forms.
17. Study of crystals can provide new chemical
information. In laboratories and industry, we can
prepare pure chemical substances by
crystallization process.
It is very useful for solid state studies of materials.
Crystal heating therapy
Crystallography is of major importance to a wide
range of scientific disciplines including physics,
chemistry, molecular biology, materials science and
mineralogy.
18. DEFINITION
• CRYSTALLOGRAPHY is simply a fancy
word meaning "the study of crystals"
• The study of crystalline solids and the principles
that govern their growth, external shape, and
internal structure
• Crystallography is easily divided into 3 sections -
- geometrical, physical, and chemical.
• We will cover the most significant geometric
aspects of crystallography
20. Properties of Crystalline Substances
1- Solidity 2- Anisotropy X Isotropy
3- Self-faceting ability 4- Symmetry
space lattice skeleton
The crystalline substances are characterise by the following properties:
21. Amorphous substances
(in Greek amorphous means “formless”) do not
have overall regular internal structure; their
constituent particles are arranged randomly; hence,
they are isotropic, have no symmetry, and cannot be
bounded by faces. Particles are arranged in them in
the same way as in liquids, hence, they are sometimes
referred to as supercooled liquids. Examples of
amorphous substances are glass, plastics. Glue, resin,
and solidified colloids (gels).
22. Curve of cooling of amorphous
substances
0
20
40
60
050100
time, min
To
Curve of cooling of a crystalline
subsatnce
0
10
20
30
40
50
60
050100
time, min
To
ab
In distinction to crystalline
substances, amorphous ones
have no clearly defined
melting point. Comparing
curves of cooling (or heating)
of crystalline substances and
amorphous substances, one
can see that the former has
two sharp bend-points (a
and b), corresponding to the
beginning and end
crystallization respectively,
whereas the latter is smooth.
23. Definition of Crystal
• A CRYSTAL is a regular polyhedral form,
bounded by smooth faces, which is assumed by
a chemical compound, due to the action of its
interatomic forces, when passing, under suitable
conditions, from the state of a liquid or gas to
that of a solid.
24. • A polyhedral form simply means a solid bounded
by flat planes (we call these flat planes
CRYSTAL FACES).
• A chemical compound" tells us that all minerals
are chemicals, just formed by and found in
nature.
• The last half of the definition tells us that a
crystal normally forms during the change of
matter from liquid or gas to the solid state.
25. Classification of crystals according
to the degree of crystallization
• Euhedral crystals
• Subhedral crystals
• Anhedral crystals
Euhedral Crystal Subhedral Crystal Anhedral Crystal
27. • Crystal faces: The crystal is bounded by
flat plane surfaces. These surfaces
represent the internal arrangement of
atoms and usually parallel to net-planes
containing the greatest number of lattice-
points or ions.
• Faces are two kinds, like and unlike.
28. • Edge: formed by the intersection of any two
adjacent faces.The position in space of an edge
depends upon the position of the faces whose
intersection gives rise to it.
• Solid Angles: formed by intersection of three
or more faces.
A
F
E
Edges………….E
Solid Angles (apices)…..A
Crystal Faces….F
Can you conclude mathematical
relation between them?
29. •Interfacial angle
we define the interfacial angle between two crystal
faces as the angle between lines that are perpendicular
to the faces. Such lines are called the poles to the
crystal face. Note that this angle can be measured
easily with a device called a contact goniometer.
30. Nicholas Steno (1669) a Danish physician and natural
scientist, found that, the angles between similar
crystal faces remain constant regardless of the size or
the shape of the crystal when measured at the same
temperature, So whether the crystal grew under ideal
conditions or not, if you compare the angles between
corresponding faces on various crystals of the same
mineral, the angle remains the same Steno's law is
called the CONSTANCY OF INTERFACIAL
ANGLES and, like other laws of physics and
chemistry, we just can't get away from it.
31. • Crystal forms: are a number of corresponding
faces which have the same relation with the
crystallographic axes.
• A crystal made up entirely of like faces is termed
a simple form. A crystal which consists of two or
more simple forms is called combination.
• Closed form: simple form occurs in crystal as it
can enclose space.
• Open form: simple forms can only occur in
combination in crystal
•The term general form has specific meaning in crystallography. In
each crystal class, there is a form in which the faces intersect each
crytallographic axes at different lengths. This is the general form {hkl}
and is the name for each of the 32 classes (hexoctahedral class of the
isometric system, for example). All other forms are called special
forms.
33. • Crystal Habit: the general external shape
of a crystal. It is meant the common and
characteristic form or combination of forms
in which a mineral crystallizes.(Tabular
habit, Platy habit, Prismatic habit, Acicular
habit, Bladed habit)
35. Crystallographic axis
• All crystals, with the exception of those
belonging to the hexagonal and trigonal
system, are referred to three
crystallographic axis.
36. Axial angles
• ∝ is the angle between b axis and c axis
• β is the angle between a axis and c axis
• is the angle between a axis and b axis
37. Crystal Systems
• We will use our crystallographic axes which we just
discussed to subdivide all known minerals into these
systems. The systems are:
(1) CUBIC (ISOMETRIC) - The three crystallographic axes
are all equal in length and intersect at right angles (90
degrees) to each other.
β
Ɣ
α
a1 a2
a3
38. (2) TETRAGONAL - Three axes, all at right angles, two of
which are equal in length (a and b) and one (c) which is
different in length (shorter or longer).
(3) ORTHORHOMBIC - Three axes, all at right angles, and
all three of different lengths.
β
Ɣ
α
c
a1 a2
β
Ɣ
α
c
a b
TETRAGONAL ORTHORHOMBIC
39. • (4) HEXAGONAL - Four axes!
Three of the axes fall in the same plane and
intersect at the axial cross at 120 degrees
between the positive ends. These 3 axes,
labeled a1, a2, and a3, are the same
length. The fourth axis, termed c, may be
longer or shorter than the a axes set.
40. • (5) MONOCLINIC - Three axes, all unequal in
length, two of which (a and c) intersect at an
oblique angle (not 90 degrees), the third axis (b)
is perpendicular to the other two axes.
• (6) TRICLINIC - The three axes are all unequal
in length and intersect at three different angles
(any angle but 90 degrees).
c
a b
β
Ɣ
α
c
a
b
β
Ɣ
α
MONOCLINIC TRICLINIC
41.
42. ELEMENTS OF SYMMETRY
• PLANES OF SYMMETRY
• Rotation AXiS OF SYMMETRY
• CENTER OF SYMMETRY.
43. PLANE OF SYMMETRY
• Any two dimensional surface (we can call it flat)
that, when passed through the center of the
crystal, divides it into two symmetrical parts that
are MIRROR IMAGES is a PLANE OF
SYMMETRY.
• In other words, such a plane divides the crystal
so that one half is the mirror-image of the other.
Horizontal planeVertical planeDiagonal plane
44. AXIS OF SYMMETRY
• An imaginary line through the
center of the crystal around
which the crystal may be rotated
so that after a definite angular
revolution the crystal form
appears the same as before is
termed an axis of symmetry.
• Depending on the amount or
degrees of rotation necessary,
four types of axes of symmetry
are possible when you are
considering crystallography
45. four types of axis of symmetry
• When rotation repeats form every 60 degrees, then we
have sixfold or HEXAGONAL SYMMETRY. A filled
hexagon symbol is noted on the rotational axis.
• When rotation repeats form every 90 degrees, then we
have fourfold or TETRAGONAL SYMMETRY. A filled
square is noted on the rotational axis.
• When rotation repeats form every 120 degrees, then we
have threefold or TRIGONAL SYMMETRY. A filled
equilateral triangle is noted on the rotational axis.
• When rotation repeats form every 180 degrees, then we
have twofold or BINARY SYMMETRY. A filled oval is
noted on the rotational axis.
46. Types of axis of symmetry
• BINARY SYMMETRY
Two fold system (180º)
47. Types of axis of symmetry
• TRIGONAL SYMMETRY
Three fold system(120º)
48. Types of axis of symmetry
• TETRAGONAL SYMMETRY
Four fold system(90º)
49. Types of axis of symmetry
Six fold system(60º)
HEXAGONAL SYMMETRY
50. Symmetry Axis of rotary inversion
• This composite symmetry element combines a rotation
about an axis with inversion through the center.
• There may be 1, 2, 3, 4, and 6-fold rotary inversion axes
present in natural crystal forms, depending upon the
crystal system we are discussing.
- - - -
51. CENTER OF SYMMETRY
• Most crystals have a center of
symmetry, even though they
may not possess either planes of
symmetry or axes of symmetry.
Triclinic crystals usually only
have a center of symmetry. If
you can pass an imaginary line
from the surface of a crystal face
through the center of the crystal
(the axial cross) and it intersects
a similar point on a face
equidistance from the center,
then the crystal has a center of
symmetry.
52. Complete Symmetrical Formula
• We can use symbol to write the
symmetrical formula as following:
1- Plane of symmetry: m
2- Axis of symmetry: 2, 3, 4, 6 and we can
write the number of the axis at up left as 3
4
3- Center of symmetry: n
For example: the complete symmetrical
formula of hexoctahedral class of
Isometric system: 3
4/m 4
3 6
2/m n
53. Intercepts, Parameters and Indices
• Absolute Intercepts:The distances from
the center of the crystal at which the face
cuts the crystallographic axes.
• Relative Intercepts: divided the absolute
intercepts by the intercept of the face with
b axis.
• Ex: if the absolute intercepts (a:b:c)are
1mm : 2mm : ½ mm, the relative intercepts
will be ½ : 2/2 : ¼ = o.5 : 1 : o.25
54. Parameters
• The parameters of the crystal face are the
intercepts of this face divided by the axes
lengths.
56. Indices
• The Miller indices of a face consist of a series of
whole numbers which have been derived from
the parameters by their inversion and if
necessary the subsequent clearing of fractions.
• If the parameters are 111 so the indices will be
111
• If the parameters are 11∞ and on inversion 1/1,
1/1, 1/ ∞ woud have (110) for indices.
• Faces which have respectively the parameters 1,
1, ½ would on inversion yield 1/1, 1/1, 2/1 thus
on clearing of fractions the resulting indices
would be respectively (112)
57. • It is sometimes convenient when the exact
intercepts are unkown to use a general
symbol (hkl) for the miller indices.
58. c
ba
O
YX
Z
A
B
C
3-D Miller Indices (an unusually complex example)
a b c
unknown face (XYZ)
reference face (ABC)
2
1 4
Miller index of
face XYZ using
ABC as the
reference face
3
invert 1
2
4 3
clear of fractions (1 3)4
59. Miller indices
• Always given with 3 numbers
– A, b, c axes
• Larger the Miller index #, closer to the
origin
• Plane parallel to an axis, intercept is 0
60. What are the Miller Indices of face Z?
b
a
w
(1 1 0)
(2 1 0)
z
61. The Miller Indices of face z using x as the reference
b
a
w
(1 1 0)
(2 1 0)
z
a b c
unknown face (z)
reference face (x)
1
1 1
Miller index of
face z using x (or
any face) as the
reference face
1
invert 1
1
1 1
clear of fractions 1 00
(1 0 0)
62. b
a
(1 1 0)
(2 1 0)
(1 0 0)
What do you do with similar faces
on opposite sides of crystal?
69. 3-Spherical Projection
Imagine that we have a crystal
inside of a sphere. From each
crystal face we draw a line
perpendicular to the face
(poles to the face).
Note that the angle is measured in the vertical plane
containing the c axis and the pole to the face, and the
angle is measured in the horizontal plane, clockwise
from the b axis.
The pole to a hypothetical (010) face will coincide
with the b crystallographic axis, and will impinge on
the inside of the sphere at the equator.
70. 4-Stereographic Projection
Stereographic projection is a method used to depict the
angular relationships between crystal faces.
This time, however we
will first look at a cross-
section of the sphere as
shown in the diagram. We
orient the crystal such that
the pole to the (001) face
(the c axis) is vertical and
points to the North pole of
the sphere.
N
EW
(010)
(001)
(011)
(0-10)
(0-11)
ρ
ρ/2
Imagine that we have a crystal inside of a sphere.
71. For the (011) face we
draw the pole to the
face to intersect the
outside the of the
sphere. Then, we draw
a line from the point
on the sphere directly
to the South Pole of
the sphere.
N
EW
(010)
(001)
(011)
(0-10)
(0-11)
ρ
ρ/2
Where this line intersects the equatorial plane is
where we plot the point. The stereographic projection
then appears on the equatorial plane.
72. In the right hand-diagram we see the stereographic projection
for faces of an isometric crystal. Note how the ρ angle is
measured as the distance from the center of the projection to
the position where the crystal face plots. The Φ angle is
measured around the circumference of the circle, in a
clockwise direction away from the b crystallographic axis or
the plotting position of the (010) crystal face
N
EW
(010)
(001)
(011)
(0-10)
(0-11)
ρ
ρ/2
EW
(010)
(001)
(0-10) (011)(0-11)
ρ
73. 1- The Primitive Circle is the circle that cross cuts
the sphere and separates it into two equal parts
(North hemisphere and South hemisphere). It is
drawn as solid circle when represents a mirror
plane.
The following rules are applied:
2- All crystal faces are plotted as poles (lines
perpendicular to the crystal face. Thus, angles
between crystal faces are really angles between
poles to crystal faces.
3- The b crystallographic axis is taken as the
starting point. Such an axis will be perpendicular to
the (010) crystal face in any crystal system. The
[010] axis (note zone symbol) or (010) crystal face
will therefore plot at Φ = 0° and ρ = 90°.
74. 4- Mirror planes are shown as solid lines and curves.
The horizontal plane is represented by a circle
match with the primitive circle.
5- Crystal faces that are on the top of the crystal ρ <
90°) will be plotted as "+" signs, and crystal faces on
the bottom of the crystal (ρ > 90°) will be plotted as
open circles “ " .
6- The poles faces that parallel to the c
crystallographic axis lie on the periphery of the
primitive circle and is plotted as "+" signs.
7- The poles faces that perpendicular to the c
crystallographic axis lie on the center of the
primitive circle.
8- The pole face parallels to one of the horizontal
axes will plotted on the plane that perpendiculars to
this axis.
75. 9- The Unit Face (that met with the positive ends of
the three or four crystallographic axes will be
plotted in the lower right quarter of the primitive
circle.
a
b
++
- +
+ -
- -
As an example all of the faces, both upper and
lower, for a crystal in the class 4/m2/m in the forms
{100} (hexahedron, 6 faces) and {110}
(dodecahedron, 12 faces) are in the stereogram to
the right
+
(001)(00-1)
+
++
+
+
(100)
(-100)
(010)(0-10)
+
++
++
+
+
(-110)
(-1-10)
(110)(1-10)
(101)(10-1)
(011)(01-1)(0-11)(0-1-1)
(-101)(-10-1)
78. Crystallographic forms
3- Dome
It is an open form made up of two
nonparallel faces symmetrical with
respect to a symmetry plane
4- Sphenoid
It is an open form made up of two
nonparallel faces symmetrical with
respect to a 2-fold or 4-fold
symmetry axis
79. Crystallographic forms
5- Disphenoid
It is an closed form composed of a four-faced form in which two
faces of the upper sphenoid alternate with two of the lower
sphenoid.
80. Crystallographic forms
Bipyramid-6
It is an closed form composed of 3, 4, 6, 8 or 12 nonparallel faces
that meet at a point
Orthorhombic bipyramed
Ditetragonal bipyramid
Tetragonal bipyramid
Dihexagonal bipyramidHexagonal bipyramid
81. Crystallographic forms
7- Prism
It is an open form composed of 3, 4, 6, 8 or 12 faces, all of which are
parallel to same axis.
Orthorhombic prism
Tetragonal prism
Ditetragonal prism
Hexagonal prism Dihexagonal prism
82. Crystallographic forms
8- Rhombohedron
It is an closed form composed of 6
rhombohedron faces,
9- Scalenohedron
It is an closed form composed of 12 faces,
each face is a scalene triangle. There are
three pairs of faces above and three pairs
below in alternating positions
105. Tetragonal prism of
first order [110]
systemTetragonal
+
1- Basal Pinacoid
(001)
(00-1)
2- Tetragonal prism of 1st order
+
++
+ (110)
+
+
+
Stereographic Projection
106. Tetragonal prism of
second order [100]
systemTetragonal
ographic projection of Tetragonal
em Forms.
+
1- Basal Pinacoid
(001)
(00-1)
2- Tetragonal prism of 1st order
+
++
+ (110)
3- Tetragonal Prism of 2nd Order
+
+
+
+
(100)
Stereographic Projection
108. systemTetragonal
Tetragonal – Bipyramid
of first order [hhl]
4- Ditetragonal prism
+
+
+
++
+
+
+
(210)
a
b
5- Tetragonal bipyramid of 1st Order
a
b
+
++
+
+
+
++
+
(111)
Stereographic Projection
109. systemTetragonal
Tetragonal – Bipyramid
of second order [h0l]
4- Ditetragonal prism
+
++
+
(210)
a
b
5- Tetragonal bipyramid of 1st Order
a
b
++
6- Tetragonal bipyramid of 2nd Order
a
b
+
+
+
+
7- Ditetragonal bipyramid
a
b
+
+
+
++
+
+
+
(111)
(101)
(211)
Stereographic Projection
113. 7- Orthorhom bic Bipyram id {hkl}
Exit
hkl
It is a closed form
com poses of 8 triangular
faces. It is the general
form of the orthorhom bic
holosym m etrical class.
Each face m et with the
crystallographic axes at
different distances {111}
or {hkl}.
117. Orthorhombic system
Crystal form
Side
pinacoid
[010]
Front pinacoid [100]
Basal Pinacoid [001]
1- Basal Pinacoid
a
b+
2- Front Pi
a
b
+
+
(100)
(001)
b++
(010)
Stereographic projection of the Orthorhombic
System Forms.
1- Basal Pinacoid
a
b+
2- Front Pinacoid
a
b
+
+
(100)
(001)
3- Side Pinacoid
a
b++
(010)
Stereographic Projection
119. Orthorhombic system
Orthorhombic front dome [h0l]
4- Orthorhombic prism
a
b
+
++
+ (110)
5- Front dome (b-Dome)
a
b
+
+
(101)
bb
++
Stereographic Projection
120. Orthorhombic side dome [0kl]
Orthorhombic system
4- Orthorhombic prism
a
b
++ (110)
5- Front dome (b-Dome)
a
b
+
+
(101)
6- Side dome (a-Dome)
a
b++
(011)
7- orthorhombic bipyramid
a
b
+
++
+
Stereographic Projection
122. Compound form
5- O rthorhom bic front dom e (b-dom e) or M acro
dom e {10l}
6- O rthorhom bic side dom e (a-dom e) or Brachy
dom e {01l}
01l
01l10l
100
Pinacoid
129. Hexagonal prism of
first order [1010]
-1010
-
a1
-a3 a2
0001
Hexagonal system
Crystal form
Basal pinacoid [0001]
Stereographic projection of the Hexagonal
System Forms.
a1
a2
-a3
+
1- Hexagonal Pinacoid
(0001)
a1
a2
-a3
2- Hexagonal prism of first order
(10-10)
+
+
+
+
+
+
a1
a2
-a3
3- Hexagonal prism of second order
+
+
++
+
+ (11-20)
Stereographic Projection
130. hhw0
-
a1
-a
3
a2
Hexagonal systemHexagonal prism of
second order [hhw0]
-
Stereographic projection of the Hexagonal
System Forms.
a1
-a3
1- Hexagonal Pinacoid
a1
-a3
2- Hexagonal prism of first order
(10-10)
+
++
a1
a2
-a3
3- Hexagonal prism of second order
+
+
++
+
+ (11-20)
Stereographic Projection
151. Monoclinic front pinacoid [100]
Monoclinic side pinacoid [010]
Monoclinic basal pinacoid [001]
Monoclinic system
Stereographic Projection
• pinacoid
Crystal form
1- Basal Pinacoida
+(001)
2- Side Pinacoida
++
+
(00-1)
Stereographic projection of the Monoclinic
System Forms.
1- Basal Pinacoida
+(001)
2- Side Pinacoida
++
3- Front pinacoid
a
+
+
(00-1)
153. Positive hemibipyramid [hkl]
Monoclinic system
Positive Hemibipyramid {hkl} or {111}
Negative Hemibipyramid {-hkl} or {-111}
hkl
7- Hemibipyramid
Front View Back View
{111} {-111}
• hemibipyramid
Negative hemibipyramid [hkl]
-
54- Monoclinic Prism
a
++
a
a
+
Positive
(101)
7-Hemibipyramid
a a
++
(111)
++
(-111)
Stereographic Projection
4- M
a
++
7
a
++
(-111)
NegativePositive
154. 5- Side Dome (a-dome)4- Monoclinic Prism
a
+
+
a
++
a a
+ (101)
+(-101)
++
(111)
+
(-111)
-
011
Monoclinic system
• Dome
- hemi-orthodome
Positive hemi-orthodome [h0l]
Negative hemi-orthodome [h0l]
- side dome [0kl]
-
101
011
side dome [0kl]Positive
hemidome [h0l]
5- Side Dome (a-dome)4- Monoclinic Prism
a a
6- Hemi-orthodome
a a
+
Positive
(101)
+
Negative
(-101)
7-Hemibipyramid
a a
++
(111)
++
(-111)
hemi-orthodome
Stereographic Projection
159. front pinacoid [100]
side pinacoid [010]
basal pinacoid [001]
Triclinic system
Crystal form
Stereographic projection of theTriclinic System
Forms.
1- Basal Pinacoida a
a
2- Side Pinacoid
3- Frontl Pinacoid
+
+
+
+
+
Stereographic projection of theTriclinic System
Forms.
1- Basal Pinacoida a
a
2- Side Pinacoid
3- Frontl Pinacoid
+
+
+
+
+
Stereographic Projection
160. Right hemi-prism [hk0]
Left hemi-prism [hk0]
Triclinic system
-
a a a a
a a
a a
a a
+
+
+
+
+
+ +
+ +
5- Hemi-b-dome {h0l}: two forms
{101} and {-101}
4- Hemi-a- dome { 0kl} : two forms
{011} and {0-11}
6- Hemi-prism{hk0} and {h-k0}
Upper left quarter bipyramid Upper right quarter bipyramid
Lower left quarter bipyramid Lower right quarter bipyramid
162. Upper right quarter bipyramid [hkl]
Upper left quarter bipyramid [hkl]
Lower right quarter bipyramid [hkl]
Lower left quarter bipyramid [hkl]
-
-
--
Triclinic system
a a
a a
a a
+ +
+ +
+ +
4- Hemi-a- dome { 0kl} : two forms
{011} and {0-11}
Upper left quarter bipyramid Upper right quarter bipyramid
Lower left quarter bipyramid Lower right quarter bipyramid
163. Crystal Morphology
• The angular relationships, size and shape of
faces on a crystal
• Bravais Law – crystal faces will most commonly
occur on lattice planes with the highest density
of atoms
Planes AB and AC will be the most
common crystal faces in this cubic
lattice array
164. Unit Cell Types
in Bravais Lattices
P – Primitive; nodes at
corners only
C – Side-centered; nodes
at corners and in
center of one set of
faces (usually C)
F – Face-centered; nodes at
corners and in center
of all faces
I – Body-centered; nodes at
corners and in center
of cell