Mineralogy
NC Minerals
Mining
Historical
Mineral Research Laboratory
Discovery of Gold
Common Minerals and Gems
State Gem Emerald
Quartz
Garnet
Lithium (Spodumene)
Mica
Olivine
Physical Properties
Interaction with light
Color
Idiochromatic
Allochromatic
Luster
Diaphaneity
Habit
Specific Gravity
Hardness
Cleavage
Fracture
Tenacity
Piezoelectricity
Symmetry
Simple Operations
Translation
Reflection
Rotation
Inversion
Complex Operations
Rotoinversion
Glide Reflection
Screw Rotation
Symmetry Elements
Mirror Planes
Centers of Symmetry
n-fold rotation
Laws
Constancy of Symmetry
Definition of a Crystal
Quasicrystals existence lead to a new definition. It is a crystal if it has an essentially sharp diffraction pattern
Techniques
Electron Micrscope
Scanning Electron Microscope
Back Scattered Electrons
EMPA
TEM
X-Ray Microscope
XRD
Monochromatic
Crystal
Powder
Full Spectrum
Petrographic Microscope
Morphology
Laws
Bravais Principle
Constancy of interfacial angles
Crystal Forms
Open Forms
Pedions
Pinacoids
Prisms
(Di)___Pyramids
Closed Forms
Dipyramids
Trapezohedra
Scalenohedra
Tetrahedra
Disphenoids
Octahedra
Dodecahedra
Form Quality
Hierarchy of Forms
Euhedral
Subhedral
Anhedral
Twinning
Cyclic Twinning
Parallel Association
Polysynthetic
Crystallography
Unit Cell
Smallest repeating unit of the lattice
Lattice Systems
Ranked by most Symmetry
1. Isometric
2. Hexagonal
3. Rhombohedral
4. Tetragonal
5. Orthorhombic
6. Monoclinic
7. Triclinic
Centering Types
Primitive
Base-centered
Body-centered
Face-centered
Bravais Lattices
Define a crystalline arrangement and its (finite) frontiers
Found by combining 4 centering types with 7 lattice systems - 14 possible after redundancies
Point Groups
Space Groups
Found by combining Point groups and Bravais lattices and screw, glide. Unit cells and all symmetry operations - 230 space groups.
Define Crystal Classes. Found by combing 14 unit cells with 4 centering types - 32 possible after redundancies
Centrosymmetric
inversion center present
Non-centrosymmetric
Polar
Enantiomorphic
Polar Enantiomorphic
Neither
Crystal Groups
Crystal Families
Crystal Systems
Triclinic
Monoclinic
Orthrohombic
Tetragonal
Trigonal
Hexagonal
Isometric
Triclinic
Monoclinic
Orthorhombic
Tetragonal
Hexagonal
Isometric
Monometric a ≠ b ≠ c
Dimetric a = b ≠ c
Trimetric a = b = c
Crystallochemistry
Chemical Bonds
Ionic
Covalent
Metallic
Homodesmic - One Bond
Heterodesmic - Multiple Bonds
Polymorphism
Same Composition, different crystalline structure
Reconstructive
Displacive
Order-Disorder
Polytypism
Isomorphism
Same crystalline structure, different composition
If two minerals are isomorphs, and have the same anionic group, they can form solid solutions
Substitution
Simple
Coupled
Interstitial
Omission
Optical Properties
Orthoscopic Illumination
Plane Polarized
Refraction Indices
Relief Lines
Color and Pleochroism
Cross Polarized
Extinction
Optical Twinning
Zonation
Birefringence
Conoscopic
Cross Polarized for interference figures
Optical Mineralogy
Optical Indicatrix
Optical Classes
Isotropic
Always extinct
Anisotropic
Uniaxial
Dichroic
Biaxial
Trichroic
Interference Figures
High Birefringence - Color on edges like calcite
Low Birefringence - Lack of color like quartz
Nonsilicates
Native Elements
Metals
Semi-Metals
Non-metals
Oxides
Metal
Semi-metal
Hydroxide
Metal bonded with OH
Halide
Ionic bonds
Sulfides
Metals bonded with S
Semi-metals bonded with S
Sulfates
SO4 anion
Carbonates
CO3 anion
Phosphates
PO4 anion
Systematics
Silicates
Nesosilicate
Isolated tetrahedron - SiO4
Sorosilicate
Double tetrahedra - Si2O7
Cyclosilicate
Tetrahedral Ring - Si6O18
Inosilicate
Single Chain - Si2O6
Double Chain - Si4O11
Phyllosilicate
Sheet - Si2O5
Tectosilicates
Tetrahedral network - SiO2
Contemporary Mineralogy
Mineral Ecology
study of the diversity and spatial distribution of mineral species
on Earth and other terrestrial planets
helps to predict the occurrence and location of mineral species
Mineral Evolution
Study of diversity and distribution over Earth's 4.5 billion year history
Shows the co-evolution of the geosphere and the biosphere
Mineral Network
Networks provide a valuable way to visualize the distribution and variation of minerals and their properties
Mineral Natural Kinds
A way to group and split mineral species
Gemology
Natural Gemstones
Precious stones
Diamond
4 C's
Cut
Shape and style of how the gem was cut
Carat
Mass
1 ct = 0.2 g
1 pt = 0.001 ct
Color
D - most clear
Z - Most yellow
Clarity
FL - no inclusions (flawless)
I3 - most inclusions
Emerald
Ruby
Sapphire
Semi-precious stones
Every other stone
Treatment
Enhance color and clarity
Heat treatment
Changes color of the gem and is irreversible
Filling
Easy to detect, but can make the gem look more smooth
Synthetic Gems
Difficult to distinguish, as chemical, physical, and optical
properties are the same
Growth Processes
Melt Growth
Uses congruent melting, and yields a high volume for a low cost
Solution Growth
Simulate natural conditions for gems that melt incongruently, and it has a low yield for a high cost
Vapor Phase Growth
Uses chemical vapor deposiition and sublimation. commonly used to make diamonds in a high cost, but high speed process
Simulants are gemstones that look like another gem, but are made of another substance. Easy to identify because all properties could be different
Extraterrestial
Extraterrestrial minerals
Most minerals found in meteorites are also found on Earth, except for kamacite and taenite
These two minerals form Widmastätten patterns when they are together and experience slow cooling
These patterns are alternating bands of kamacite and taenite
Plessite - a fine-grained mixture of kamacite and taenite forms last and fills in the gaps
Inclusions in the patterns are Troilite nodules. Black FeS inclusions
Kamacite samples have Neumann lines, which is twinning formed by impact shockwaves
Pseudometeorites
Because of the value of meteorites, it is an attractive idea to construct lookalikes that can look comparable on occasion
Representation
Haüy’s law - all crystal faces make intercepts on the
crystallographic axes
Miller Indices - Notation system for planes in lattices - h,k,l used
Can use the miller indices to make stereographic projections