Mineralogy: Defining Minerals

Mattu University - Mineralogy Module

• Defines "mineral" as a naturally occurring chemical compound or element forming Earth's rocks, regardless of economic value

• States minerals must be naturally occurring and have definite chemical composition, typically formed from inorganic processes

• A mineral must be a solid crystalline substance, excluding liquids and gases

• Organic substances from plants and animals do not constitute minerals

• Describes the uniqueness of each mineral due to its specific chemical composition and arrangement

• Notes over 5,000 mineral species are known, with 100+ new descriptions annually

• Provides familiar mineral examples: quartz (SiO2), calcite (CaCO3), pyrite (FeS2), gypsum (CaSO4·2H2O), gold (Au), silver (Ag), copper (Cu), diamond (C), graphite (C), garnet (Mg3Al2Si3O12), ice (H2O)

• Lists less familiar minerals: apatite (Ca5(PO4)3OH), olivine (Mg2SiO4), pyroxene (MgSiO3), muscovite (KAl2(AlSi3)O10(OH)2), feldspar ((Na,K)AlSi3O8 or CaAl2Si3O8) rocks consist of solidified minerals/mineroids

• A rock can be composed of one or more minerals combined

• Classifies minerals as homogeneous solids with regular structures, existing within rocks, ores, and Earth's crust deposits

Mineral Formation

• Lowering a liquid's temperature below its freezing point can initiate crystallization
• The process is illustrated for water, with ice crystals forming at or below 0°C
• Magma (hot molten rock) cools and forms silicate minerals like olivine or feldspar at around 1000°C
• Crystallization can also occur via precipitation as liquids evaporate from a solution
• A solution forms when one chemical dissolves into another substance
• As water evaporates from a salt solution, concentration increases to saturation, leading the salt to drop out as crystals

Mineral Classification by Economic Importance

• Economic minerals are those explored for their economic value (Au, Ag, Cu, Fe, etc.)
• Rock-forming minerals constitute rocks (e.g., silicate minerals)

Mineral Classification: By Origin/Genesis

• Primary minerals form directly from magma cooling (e.g., olivine)
• Secondary minerals form via secondary processes like sedimentation/metamorphism (e.g., malachite)

Mineral Classification Based on Rock Naming

• Essential minerals affect rock naming (e.g., quartz in granite dictates it must contain quartz, feldspar, and mica)
• Accessory minerals don't influence rock naming (e.g., zircon in granite)

Mineral Classification Based on Chemical Composition

• Native elements occur uncombined
• Native elements constitute a small presence in most mineralogy, typically metals (Au, Ag or Pt) or diamond, a nonmetal
• Sulphates contain the sulphate ion (SO4)2- , for example: Gypsum (CaSO4.2H2O), Barite (BaSO4), Celestite (SrSO4) etc
• Oxides contain an element combined with oxygen, for example: Magnetite (Fe3O4), Hematite (Fe2O3), Corundum (Al2O3) etc
• Halides contain a cation combined with a halogen
• Carbonates contain the carbonate ion (CO3)2
• Sulphides contain a cation combined with sulphur (S2), for example: Pyrite (FeS2), Galena (PbS) etc
• Phosphates contain phosphate ion (PO43)

Mineral Identification - Introduction

• Mineral identification differentiates geological sample from other geological materials and minerals.
• Minerals are identified based on their physical or optical properties, which are controlled by chemical composition and crystalline structure.

Mineral Properties

• Crystal habit/form includes traits which describe mineral species.
• Mega-scoping properties can be identified in hand specimens with the naked eye.
• These properties include crystal habit, color, streak, luster, density, hardness, cleavage, fracture, and tenacity.

Crystal Form or Habit

• Crystal habit describes the favored growth pattern of mineral crystals, either individually or in aggregate

• It may not bear relation to a single, perfect crystal form of the same mineral

• Crystal form is the geometric shape developing without environmental restrictions, identifying mineral specimens

• Adjectives describing habit: equant, prismatic, tabular

• Crystal aggregates termed equant or prismatic, while thin, flat crystals may be termed 'bladed'

• Crystalline aggregation type: acicular, filiform, capillary or fibrous indicate long, slender needles, hair, or thread-like forms

• Crystal habit definitions:

  • Equant crystals possess approximately the same side length in every direction (garnet)
  • Prismatic crystals elongated in direction (tourmaline)
  • Tabular crystals appear plate-like in shape
  • Bladed habits have collection of knife blade-like crystals (gypsum)
  • Foliated crystals separate into leafy structures (Latin for leaf - folium)
  • Micaceous minerals are thin, flat sheets (muscovite)
  • Lamellar habits form thin scales or plates (schist)
  • Plumose habit displays fine, feathery scales (pluma, feather)
  • Acicular aggregate of crystals containing slender crystals (natrolite)

• A filiform mineral of thread-like filum exhibits hair-like threadlike filaments

• A fibrous mineral of long fibers exhibits clumps of sinewy, stringy, or hair like fibers

• Dendritic crystals exhibits branching growth (native copper)

• A oolitic crystal forms small spheres resembling fish roe

• Amygdaloidal crystals show small, almond-shaped nodules or amygdules

• Atoms arranged linearly may form long, slender needles

• Atoms in box network yield cube-like crystals

• Quartz crystals form long, hexagonal crystals of small size ( mm - cm )

• Physical and chemical properties are size-independent in single crystals

Color

• Although the first thing one notices, the color is generally not a good property to identify minerals

• Novices can make incorrect assumptions regarding colour

• Many can have different colors or be identical to each others colours

• As an exception, color can sometimes by identifying (olivine and epidote are green)

• Minerals with a variety of colors are called allochromatic (quartz can be clear, white, blank, pink blue or purple)

• Color is related to the behaviour of light

• Minerals with distinctive colors are characteristic and can be easily identified by their colors

• Light color is determine by its wavelength

• Certain elements have electrons which absorb certain wave lengths

• Transition elements can cause minerals to always be a certain color by being part of the mineral

• Traces influence mineral color

• Chromium, Cr produces orange-red color in crocoite

• Copper produces the azure blue color in azurite

• Iron, Fe produces the red color of limonite

• Manganese, Mn produces the pink color of rhodochrosite

• Quartz is colorless when pure, as its color can vary by impurities like ti and fe

• Fluorite has the most color variance with: purple, blue, green, yellow, colorless, brown, pink black and ore

Luster

• Luster defines a mineral's surface appearance in reflected light

  • Metallic has shiny or metal-like appearance, usually opaque with dark streak (ex. Galena/Pyrite)
  • Adamantine is lustrous like a polished metal surface

• Non-metallic lusters include:

  • Vitreous lustre looks glassy (e.g clear quartz).
  • Resinous resinsous such as sulfur
  • Pearly - iridesecent and pearl-like (apophyllite)
  • Greasy has apperance of oil coated surface (nepheline)
  • Silky looks fibre-like (gypsum, serpentine, malachite).
  • Adamantine has a brilliant lustrous appearance like diamonds

• Submetallic

  • Submetallic minerals have luster like metal but are duller and less reflective/ occur in high refractive index such as sphalerite/cuprite

• Eathry/dul luster is the lack of luster (such as kaolinite) and have coarse granulations which scatter light towards all directions

• Vitreous luster is common and seen in transparent or translucent minerals

• Resinous luster resembles resin, chewing gum or smoothes surface

• The principle example is solidifies resin, Amber

• Peraly lustre minerals are of tranpsarent, co-panal sheets

• They reflect light to give them a pearl luster

• Can include Minerals such as muscovite

• The greasy lusture exhibits a fatty appearance which often occus contains a abundance of greasy micro bodies

• Silky reflects parallel fine fibres of examples like the satin spar/ gypsym variety

• Waxy lustre resembles waxes such as Jade

Streak

• The streak is color produced when scratching on a streak plate such as porcelin.
• It related to the color but relates to the color of powdered version of material
• Two minerals with similar may appear different in the powdered version
• Hematite is blood red, while galens is lead grey
• Pyrite crystal has a yellowish and a black streak

Hardness

• Hardness defines minerals resistance to abrasions or scratching

• Measures strength of the structure in terms of relative strength of chemical bonds

• Stronger has greater levels of hardness

• Minerals are packed together and have tighter more string covalent bonds are the hardest

• A mineral can only be scratched by something with stronger chemical strength

• A hard mineral can scratch a softer one in most cases (the Moh's Hardness scale)

• The Softest has Vander waals bonds or metallic components

• Hardiness comes from the chemical composition

• The mohs scale ranks minerals hardness with talc at 1 and ending with diamond at 10

• You can check using a patite

• Check If hardiness of minerals varies it has hardness greater or less than 5

• Note as hardness scales

Cleavage

• Cleavage occurs via weaker atomic planes

• A hard object separates along these points

• Weak bonds such as mica or orholite and perfect cleavage occurs

• Covalent bonds provide less to no cleavage and can be strong

• Ionic bonds produce excellent cleavage and are relatively week leading to geometric polyhedrons

• Octahedral cleavage comes from fluoride/ cubic cleavage from halite and rhombohedral calcite

• The angle between cleavages is often diagnostic

• Pyroxene and amphiobilite groups are distinguished by these acute angles

• three identical can only indicate cubic /prismatic/rhombohedral

• Note do not attempt to sever specimens

• Breakage from cleavage is usually induced after being pulled from the earth which leads into these plains

• See cleavage without breaking

Properties : Parting

• Parting also relates to plane crystal that can be weakened by force
• A mineral subjected stress shows some properties and may not in some specimens

Properties: Fracture

• Random directions of weakness can lead to fracture

• There are some that appear like

• Conchoidal fractures show curved surfaces that appear smooth

• Fibrous/splintery is similar to breaking wood

• Hackly shows sharp jagged edges

• Irregular - rough irregular surfaces

Properties: Density and/or Specific Gravity

• Density's volume/mass ration at the object
• Atoms affect specifics
• The crystal affects its organisation
• The specific gravity and atoms can be used to identify diagnostics and give specifics
• higher an atomic number cation, the higher the specific gravity

Properties: Tenacity

• Mineral deformation under external force
• Tenacity describes behaviour of deformation from cutting and striking sources
• Minerals tend to be: brittle or flexible
• Most are easily broken and some material requires specific amount of stress
• Elasticity leads to original shape
• Malleable or ductility leads to flattening or thin wiry states
• Sectile means slices can be made

Propeties: Fluorescence and Pospphoresence

• Fluorosence is when they light up x-rays or UV light radiation is presented.
• Posspforescence can indicate afterlight
• This differs between samples
• It happens because elements used causes it's

Properties: Magnetism

• Magnetic minerals come from magnetic elements
• Diagetic minerals have no such components while diamonds due
• Ti, Cr, V, Mn, Fe,Co, Ni, and Cu can form such cases.

Properties: Transparency

• Ease of light in transmitted substance

• Can be found I cut/gemstones

• Transparent stones that show clear outlined objects

• semi-trans that are blurred but great deal of the light is transmitted

• Translucent minerals shows little light at most and are not clear

• Semi tranluscent are the light at edges

• Opaques never trasnmit

Properties: Other Unique/Special Properties

• Some minerals are defined by special sound, test, reactivity ,acidicity, or feel
• Testes can differentiate between halite-salty, sylvite-bitter, borax-sweet,
• Graphite and Molybdenine are greasy like materials.
• Oder is strong and only appears when excavated.
• jadeite has sonic components, ring bell quality

Genesis of Mineral, Ion, its Radii and Coordination

• Earth's materials are organized as minerals and rocks, made of atoms and elements
• Atoms: Modern atomic theory describes atoms with neutrons, prootons and electrons components: +1, 0 and -1 charge
• Proton and nuetron have similar relative mass
• Electron is negligible
• The core that is most of the mass is most distinct to proton and neutrons and gives unique number in nucleus

Structural Classificiation of Minerals

• Crystals make it up in distinct form

• crystallography is the classification, with six classes: Cubic, Triganol, Hexagonal. etc

• Crystaline solids follow and adhere to the class

• The first is cuibuc follow axes directions

• isometric are symmetric

• Rocks tend to break apart/brittle

• Pyrite are known as fool's gold and are metallic

• Tetra follow three directions and are equal in length

• Idocrase is in this arrangement

• Hexa consist s of four axes and symmetrically paced like Apatite

• One of the axes must symettriacl

• Orthorombic are crystals wiuth different lengh perpedicular

• Barites show these traits

• Monolinic are 3 and two must follow

• gyspsom follows them and some are soil amendments

• triclinic follow all dimensions with some axinites showing

• Axes are set but angles and placement changes it all

• Albites fall under which can also affect the silca

Optical Properties - Introduction

• Optical properties help identify microscope behaviors of minerals

• Science deals with optical properties is mineralogical

• Optical properties relate the chemistry

• Some importance traits are

• composition estimates of min

• Petragenis traits

• deals with rock samples

• Specialized microscopes are used

• most deal with optical scopes

• and how they create a magnified image

• They must be set and allow movement

• Bulbs provide the white source of light

• Wc makes it for lower polarisation

• Specimens follow these directions

• 3 different parts are powder, rock and crystal types

• Thin sections used

• used for identification to class

The Nature Of Light

• Electromagnetic energy forms light
• Vacuum at 3*10 to the 8 power
• the crystals create these paths
• Polarize it perpendicular
• Filters and alter beams to follow the energy paths

Reflecting

• Reflect leads returning with to original
• rare media has light
• That of the insidnece
• Angles to make the normal to reflect

Polarizing Microscope Use of Transmitted light

• a light can be be polarized by vibrational waves

• Interaction with matter to allow polarization

• Used by 2 lighting setups depending on minerals

• Black = Graphite, limonite

• Polariser is added to have this occur

• The Polarizer/Analyzer are the same as crosshairs polar

• Allow intensity and depth

• A condensor/conosopic are used to converge

• Stage moves around on graduated shape circle

• It helps to secure thins sections

• An objective is four /six of such cases

• the nose also carries a slot to insert plates, mica, plat

• After is analyzer from all

• An eye piece is must top of this

• magnification varies 4 and 7x etc

• and contains crosswirs

• Total magnification = the eye piece and objective power

• analysis follows

Petragophic Analytics

• Data on this will follows
• Modal percentages
• Texture/fabric that includes fossils
• Section type and minerals found
• thin vs thick
• in polished thins sections/crossed polarisera are used

Characteritics Plane Polarisers

• a sample can be shown as
• opacue/ mineral types
• Crystal style/shapes
• Color and Cleavage

Characts Seen are CrossPolarisited

• antistropic vs isoptropic
• interfence of coors
• twinning and zoning

Light Color

• Only in PPL
• Changes with intensity
• Selective absorption
• crystal rotate to show absorbance in light

Relief

• measurment of refractive differences
• Visual is PPL
• Olivine has hgih vs plagioclose has low

Interference colours

• Crossed poles
• Quantifying by the different indexes of refraction
• 4.4. Uniaxial minerals, Biaxial minerals,Pleochroism

Uniaxial and Biaxial classes

• Anisotropic minerals are subdivided in

• Minerals can contain 1 type/2 types of the above traits

• Reorentin properties are not available though

• Rls characterize

• Polochroism is from vibration directions

• The polarization creates the rotation of light

• color comes from some absrobance type

• and creates such traits with light that is known

• a physical way Is refartive

The chemistry of interactions

• travel of ligt by different refraction points
• Snell states it through refraction
• Mineral properties follow those interactions
• velocity changes when entering

Structure Chem of Minterals Notes

• Chemistry of Minerals

• Structure similarities

• Introduction of crystal structure

• Characterized Geometric structural atoms in regular and repeating arrays in 3d

• Most Minerals Conceptualize as anions

• filling cation that coordinate

• morphis an element

• coordinates a principle geometry for blocks

• ionic build subcations

• number / anions or coordination build

• Isomorphis is how element's can represent equiaivilnets in minerals because structural differences

• isomorphic groups can the used between oxide, carbon, sulfate categories

• Relative size coordination is equal and symmetry applies to structure/behaviour

• Polymorphic" many forms" is a single chemical compound with differing structures and polymorphs

• Polymorphic groups follow but Atomic structural change

• usually in Temps, Bonds and different atoms

• Arrangement to the temp/volume

• Crystal forms of a new form and minerals

• Temp increased leads to more vibration

• The phases to new forms will change based in the crystal struct

• polymorphic transformations alter elements

• Stability and structural types

• Structural ordering and how

• energy is changed which can to temp and pressure

• This includes: Reconstructive Transformations

• 1/2 Diplacesive trans and ordering changes

• 2 Reconstructive Transformations/diplaces and ordering

• extensive arrangement

• usually in pressure, volume _Rate is changes to change at high rate

• unstable can occur for small time

• Metable Carbon polymorph

• Diplacesive Transformations

• small changes

• no bonds break

• change shape at smaller amount

• non unstable occurs

• Pressure can alter for the quarts above and at the temperature

• The forms and rock types

• The transformation cannot for Earth face

• OrderDisorder Transformations a. order/discorder is altered b. perfect can at -273 degrees c. temp can rise and is in the disorder system d. definite temp for changes e. Compound ex: KAl3O8 the stage at high temp and type: Monoclinic, Di/Graph, Alum, Cac03 and Silcone f. Carbons from meta at a high level

• Polymorph is a similar minerals by how the external faces looks

  • But has a difference existence
  • looks similar by their faces looks face:
    • and is referred to as a pseudo/alteration for the forms
  • can be different by
    • substitution for the forms
    • The quatetz for fluoros, and are said after such
    • alter process to a thinning if crust

• 3 for alter is both partial with partially composed minerals

• And results with alter that has Anhydrite or gyusim products

• Substitutions can be on element or crystal forms

Atomic Subscription and Solid

• Element proportion of a min is shown from solid subscription
• In oxide by using % and atomic
• show the components of solid solutions
• Atomic solution is the new the old is the solution where has to be: different to the: +1 for the substitution < 15%
• Homoginies are variable in structure
• Can create location
• Function of types
• Ions of atom

Elements of Solid Form

• Elements are equal in many charge
• Solution results in either or the both cases:
• With partial some solutions, charges are with
• Higher of the elements at higher and greater temperatures are: Ionic K Na and Ca

Introduction to Intro to minerals

• Minerals are classification by how their have what makes native halides of supahtes

• Native metals have been shown by native types

• Metallic elemts is the most common for quantity and compounds, and those and are metals that have: electricity and conductance

• These often the metal type gold/si/cu that follow that traits to the top for the most part as metal's do

• Nonmetals have those that cannot conduct and a strong bond

• nonmetals Graphite/Sulfur

• graphite is used with carbon in steel

Introduction To Metals pt 1

• Metallic elements are comparatively small
• Iron compounds are what most industries need
• Alloys contain silver, coopper that has and different traits with distinct crystals
• Gold has traces up to less than a per cent. Of si for silveriferous. And at a percent alloys are formed

Siluer/ Gold Group

• Native metal copper used amalgam for etc. And are most important
• Of of trade is it, A is it not always all from. Always it is

Copper notes

• tiny crystals are not always flat
• Better for crystallization
• Mallebility
• Borax is produced as blue solution created and it is very soluble
• Alloys may be distinguished
• sand and stones can occur with these
• Old volcanoes can use calcs

Silver

• in quartz stone s can get with carbonates
• flat irregular, can get found by:
• often gold, copper occur and that the elements with that can follow here
• color is often gray with tarnished
• No cleavage exists
• ductile and are great with electricity

Density to Properties

• density Is measured for purity
• Found via veins, some by the rocks them selves. Old have found to be in sulphide,copper
• some weathered can have secondary richness to which they hold themselves
• quantity/general form with gold properties
• There are properties can be seen
• gold to the native types
• Finnshed for the most which the with can have for that there by the presence will for the powers Microscope
• Always minute can help
• Visible grains for the finders with the mixture
• well Formed and have is occur have the Gold

Gold types 1

• Distorted by the processes and type pressure

• Gold have have alloys

• silver and and and and often for of the is copper rare. have

• to is Contains it to of silver, rare Gold is to trace Gold a to contains Gold a of percentage With Gold At 6' per present is a

• Elect are the all alloy colour then percentage reaches Alloy. the will when alloy The gold the with by color gold a from various

• And there is

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• when properties. high With, it yellow Is streak. there is its and the of course,. course the Gold

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Notes for Platinums.

• Other. are contain all the in Metal Nature Also - is As always the metal Nature. Found is As Platinum:
• Often also also or in smaller grain
• Is grey streak Color - The .gray streak Color - The Platinum
• Acid. Not by are And
• Is it. 5 is and Its -4 to . to this The
• Is has is Is also the -5, also and and and to and to and To To Platinum - Also be - Is it

Occurence' Notes:

• platinum-1. is and beach or by placer for known. Can - are with sometimes that.18 and which
• igneous to small can with also for which - is There
• 6.1.2 Is:
• and have This: are the with

Classification of Clay

• A clay earth/natural is any clay for all what are with the The there the with
• clay and Clay clay that are This with time 1% from to is and is of
• of that and as sediments product water what is This time in is that And of with to the by is or that is this, and

Properties and Functions:

• Most in have has. earth and for to to .
• some that in Aluninum in in There to Some and aluminumsiloxines al hydious some of There To and all For
• in clay for or