introduction to mineralogy dr tark hamilton chapter 2 lecture 4 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Introduction to Mineralogy Dr. Tark Hamilton Chapter 2: Lecture 4 PowerPoint Presentation
Download Presentation
Introduction to Mineralogy Dr. Tark Hamilton Chapter 2: Lecture 4

Loading in 2 Seconds...

play fullscreen
1 / 20

Introduction to Mineralogy Dr. Tark Hamilton Chapter 2: Lecture 4 - PowerPoint PPT Presentation


  • 178 Views
  • Uploaded on

Introduction to Mineralogy Dr. Tark Hamilton Chapter 2: Lecture 4. Camosun College GEOS 250 Lectures: 9:30-10:20 M T Th F300 Lab: 9:30-12:20 W F300. Asterism Crystal form Crystal Habit Chatoyancy Cleavage Colour Density (S.G.) Fracture Fluorescence Hardness. Luminescence Lustre

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Introduction to Mineralogy Dr. Tark Hamilton Chapter 2: Lecture 4' - flower


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
introduction to mineralogy dr tark hamilton chapter 2 lecture 4

Introduction to MineralogyDr. Tark HamiltonChapter 2: Lecture 4

Camosun College GEOS 250

Lectures: 9:30-10:20 M T Th F300

Lab: 9:30-12:20 W F300

physical properties of minerals interplay with light
Asterism

Crystal form

Crystal Habit

Chatoyancy

Cleavage

Colour

Density (S.G.)

Fracture

Fluorescence

Hardness

Luminescence

Lustre

Magnetism

Parting

Phosphorescence

Piezo-, Pyroelectricity

Play of colours

Radioactivity

Tenacity

Streak

Physical Properties of Minerals(Interplay with light)
crystallography faces
Crystallography (faces)

Pyritohedron 12

Perfect & Poor Dodecahedron 12

Rhombohedron 6

Perfect & Poor Octahedron 8

Perfect & Poor Cube 6

crystallography
Crystallography
  • External & internal crystal form
  • Methods: Visual, microscopy, refraction, XRD, ED, SEM, TEM
  • Forms: Pedion, Pinacoid, Dome; (hkl)
  • Dihedral angles: (<180°, internal)
  • Symmetry elements: 2- 3- 4- 6-rotation, screw axes, mirror planes, glide planes
6 crystal systems ch 6 p 128 129 32 crystal classes grouped by center of symmetry or none
6 Crystal Systems (Ch.6: p.128-129) 32 Crystal Classes grouped by center of symmetry or none
  • Triclinic: all different edges and angles, a ≠ b ≠c , no 90° angles, 1= no sym, Ī = centre
  • Monoclinic: all different edges, a ≠ b ≠c , β> 90° , α=γ=90°, symmetry: 2,m, 2/m
  • Orthorhombic: all different edges but all 90° angles, a≠b≠c , α=β=γ=90°: 222, mm2, 2/m 2/m 2/m
  • Tetragonal: 2 different edges, all 90° angles, a=b≠c , α=β=γ=90°: 4, 4bar, 422, 4mm, 4bar2m, 4/m, 4/m 2/m 2/m
6 crystal systems ch 6 p 128 129 32 crystal classes grouped by center of symmetry or none1
6 Crystal Systems (Ch.6: p.128-129) 32 Crystal Classes grouped by center of symmetry or none
  • Tetragonal: 2 different edges, all 90° angles, a=b≠c , α=β=γ=90°: 4, 4bar, 422, 4mm, 4bar2m, 4/m, 4/m 2/m 2/m
  • Hexagonal (hexagonal):2 different edges, 120° & 90° angles, a1 = a2= a3 ≠ c , α= α= α = β = 90° γ = 120°: 6, 6bar, 622, 6mm, 6bar m2, 6/m, 6/m 2/m 2/m
  • Hexagonal (trigonal):3 equal edges, 120° & 90° angles, a1 = a2= a3 = c , α = β = 90° γ = 120°: 3, 32, 3m, 3bar, 3bar2/m
6 crystal systems ch 6 p 128 129 32 crystal classes grouped by center of symmetry or none2
6 Crystal Systems (Ch.6: p.128-129) 32 Crystal Classes grouped by center of symmetry or none
  • Tetragonal: 2 different edges, all 90° angles, a=b≠c , α=β=γ=90°: 4, 4bar, 422, 4mm, 4bar2m, 4/m, 4/m 2/m 2/m
  • Hexagonal (trigonal):3 equal edges, 120° & 90° angles, a1 = a2= a3 = c , α = β = 90° γ = 120°: 3, 32, 3m, 3bar, 3bar2/m
  • Isometric (cubic): 3 equal edges, 3 90° angles, a1 = a2= a3 , α = β = γ = 90°: 23, 432, 4bar3m, 2/m3bar, 4/m3bar2/m
habit face development
Habit – Face Development
  • Euhedral: good, well formed faces, taking its characteristic crystal form. E.g. hexagonal quartz prisms or cubic pyrite
  • Subhedral: Some good faces - some curved
  • Anhedral: Mineral lacking crystal faces, curved, rounded, embayed, irregular
crystal habit growth shape environmentally controlled
Granular Micaceous Bladed

Fibrous Acicular Radiating

Dendritic Mammilary Colliform

Vuggy Concentric

Oolitic/Pisolitic

Crystal Habit (Growth Shape)(Environmentally controlled)
crystal habit growth shape other terms
Crystal Habit (Growth Shape)Other terms:
  • Compact: too fine grained for naked eye e.g. Kaolinite
  • Massive: Lacking crystal faces, multiple fine grains e.g. olivine in dunite, goethite
  • Sugary: mass of fine crystals, e.g. gypsum, anhydrite
  • Earthy: massive, compact, dull, e.g limonite
crystal habit growth shape other terms and interpretation
Crystal Habit (Growth Shape)Other terms: (and interpretation)
  • Banded: layers with colours or compositional differences, planar version of concentric, e.g. agate, fluorite (changing fluid composition, trace elements, oxidation)
  • Blocky: euhedral but similar in all dimensions e.g. analcite, feldspar (grew in free space or unencumbered, e.g. magmatic)
  • Botryoidal: mammilary, reniform a curved bumpy grape-like mass with involute intersections often radial or concentric in cross section e.g. chalcedony, prehnite (growth during fluid concentration, dessication, at water table)
  • Fibrous: thin filaments often curved e.g. asbestos (Grew in free space, across a vein)
crystal habit growth shape other terms and interpretation1
Crystal Habit (Growth Shape)Other terms: (and interpretation)
  • Geode: hollow rock cavity or concretionary mass with concentric layering or drusy crystals, e.g. barite, calcite, amythest often with shelves or half filled geopedal structures showing way up (shallow void or solutional space often above water table)
  • Triple point: granular often monomineralic with 120° grain boundaries, common in quartzite & marble (equal pressure in all directions)
  • Lamellar, foliated: layered e.g. graphite, molybdenite (pseudo-hexagonal crystal form)
  • Needles, whiskers: Longer than wide or thick = acicular e.g. apatite, millerite(preferential growth in one direction or form, quench, bacterial)
crystal habit growth shape other terms and interpretation2
Crystal Habit (Growth Shape)Other terms: (and interpretation)
  • Needles, whiskers: Longer than wide or thick = acicular e.g. apatite, millerite(preferential growth in one direction or form, quench, bacterial)
  • Prismatic: elongate euhedral forms e.g. pyroxene, amphibole, quartz (Commonly monoclinic or hexagonal)
  • Pisolitic: Large concentric concretionary or residual masses, e.g. bauxite, cave pearls (formed at or below water table by solution precipitation processes)
  • Tabular: similar length & width but lesser thickness e.g. feldspars (Commonly monoclinic, orthorhombic, tetragonal, grew in free space, e.g. magmatic)
cleavage directions forms
Cleavage directions & forms

Dodecahedral 6 @ 116.6°

Cubic 3 @ 90°

Octahedral 4 @ 109.5°

Rhombohedral 3

No 90° or 60°/120°

Prismatic 3 = (2 + pinacoid)

Pinacoidal, Basal 1

introduction minerals light

Introduction Minerals & Light

Reflectance, scattering, transmittance, refraction, absorption, energy effects…

diaphaneity ability to transmit light
Diaphaneity:ability to transmit light
  • Transparent: Transmitting some light; quartz, calcite, halite, ulexite, gems
  • Translucent: Diffuse transmittance of light, cloudy bright, bathroom glass, most silicates, sulphates, carbonates, salts; moonstone, gypsum, anhydrite, aragonite
  • Opaque: Blocks transmittance of light even on thinnest edges, metal sulphides & oxides; Magnetite, Pyrite, Galena, Copper
slide17
Lustre:appearance in scattered + reflected light(interaction between photons of visible light and bonding electrons in mineral)
  • Metallic: highly reflective, shiny
  • Sub-Metallic: darkly reflective
  • Non-metallic: various, glassy ceramic-like
colour
Colour
  • It is a spectral thing ROYGBIV long short
  • Depends on energy, E = h ν = h c/λ
  • It depends on our eyes: Gold absorbs blue so it looks yellow!
streak
Streak
  • True colour of powdered mineral (depends on compound not structure)
luminescence
Luminescence
  • Mineral absorbs usually higher energy and emits cold light (not incandescence)
  • Triboluminescence: shock emits light, quartz; hammers, explosions, quakes
  • Thermoluminescence: heat emits light, caused by cosmic ray damage, dating use
  • Phosphorescence: stores & emits light
  • Fluorescence: uV emits visible light on-off