Mineralogy

Crystallography

by Lisa Rogers

TRIGONOMETRIC FUNCTIONS

by MAMADOU BARRY

System Engineering

by Hend Khalid

hydrogen

by racher dalagan

Solid Solutions have Zonation

Opposites

Gray Line = Phylogeny

Green Line = Contrast

Blue Line = Expanding Concept

Red Line = Direct Concept Connection

Yellow Line = Hierarchy

Very High Symmetry

High Symmetry

Low Symmetry

Groups divided into Families

Families Divided into Systems

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

Extraterrestial

Pseudometeorites

Because of the value of meteorites, it is an attractive idea to construct lookalikes that can look comparable on occasion

Extraterrestrial minerals

Most minerals found in meteorites are also found on Earth, except for kamacite and taenite

Kamacite samples have Neumann lines, which is twinning formed by impact shockwaves

These two minerals form Widmastätten patterns when they are together and experience slow cooling

Inclusions in the patterns are Troilite nodules. Black FeS inclusions

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

Gemology

Synthetic Gems

Simulants are gemstones that look like another gem, but are made of another substance. Easy to identify because all properties could be different

Growth Processes

Vapor Phase Growth

Uses chemical vapor deposiition and sublimation. commonly used to make diamonds in a high cost, but high speed process

Solution Growth

Simulate natural conditions for gems that melt incongruently, and it has a low yield for a high cost

Melt Growth

Uses congruent melting, and yields a high volume for a low cost

Difficult to distinguish, as chemical, physical, and optical properties are the same

Treatment

Enhance color and clarity

Filling

Easy to detect, but can make the gem look more smooth

Heat treatment

Changes color of the gem and is irreversible

Natural Gemstones

Semi-precious stones

Every other stone

Precious stones

Sapphire

Ruby

Emerald

Diamond

4 C's

Clarity

I3 - most inclusions

FL - no inclusions (flawless)

Z - Most yellow

D - most clear

Carat

Mass 1 ct = 0.2 g 1 pt = 0.001 ct

Cut

Shape and style of how the gem was cut

Contemporary Mineralogy

Mineral Natural Kinds

A way to group and split mineral species

Mineral Network

Networks provide a valuable way to visualize the distribution and variation of minerals and their properties

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 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

Systematics

Silicates

Tectosilicates

Tetrahedral network - SiO2

Phyllosilicate

Sheet - Si2O5

Inosilicate

Double Chain - Si4O11

Single Chain - Si2O6

Cyclosilicate

Tetrahedral Ring - Si6O18

Sorosilicate

Double tetrahedra - Si2O7

Nesosilicate

Isolated tetrahedron - SiO4

Nonsilicates

Phosphates

PO4 anion

Carbonates

CO3 anion

Sulfates

SO4 anion

Sulfides

Semi-metals bonded with S

Metals bonded with S

Halide

Ionic bonds

Hydroxide

Metal bonded with OH

Oxides

Semi-metal

Metal

Native Elements

Non-metals

Semi-Metals

Metals

Optical Mineralogy

Optical Indicatrix

Interference Figures

Low Birefringence - Lack of color like quartz

High Birefringence - Color on edges like calcite

Optical Classes

Anisotropic

Biaxial

Trichroic

Uniaxial

Dichroic

Isotropic

Always extinct

Optical Properties

Conoscopic

Cross Polarized for interference figures

Orthoscopic Illumination

Cross Polarized

Birefringence

Extinction

Zonation

Optical Twinning

Plane Polarized

Color and Pleochroism

Relief Lines

Refraction Indices

Crystallochemistry

Isomorphism

If two minerals are isomorphs, and have the same anionic group, they can form solid solutions

Omission

Interstitial

Substitution

Coupled

Simple

Same crystalline structure, different composition

Polymorphism

Polytypism

Order-Disorder

Displacive

Reconstructive

Same Composition, different crystalline structure

Chemical Bonds

Heterodesmic - Multiple Bonds

Homodesmic - One Bond

Metallic

Covalent

Ionic

Crystallography

Crystal Groups

Trimetric a = b = c

Dimetric a = b ≠ c

Monometric a ≠ b ≠ c

Crystal Families

Orthorhombic

Crystal Systems

Isometric

Hexagonal

Trigonal

Tetragonal

Orthrohombic

Monoclinic

Triclinic

Unit Cell

Lattice Systems

Bravais Lattices

Point Groups

Define Crystal Classes. Found by combing 14 unit cells with 4 centering types - 32 possible after redundancies

Non-centrosymmetric

Neither

Polar Enantiomorphic

Enantiomorphic

Polar

Centrosymmetric

inversion center present

Space Groups

Found by combining Point groups and Bravais lattices and screw, glide. Unit cells and all symmetry operations - 230 space groups.

Define a crystalline arrangement and its (finite) frontiers

Found by combining 4 centering types with 7 lattice systems - 14 possible after redundancies

Centering Types

Face-centered

Body-centered

Base-centered

Primitive

Ranked by most Symmetry 1. Isometric 2. Hexagonal 3. Rhombohedral 4. Tetragonal 5. Orthorhombic 6. Monoclinic 7. Triclinic

Smallest repeating unit of the lattice

Morphology

Crystal Forms

Twinning

Polysynthetic

Parallel Association

Cyclic Twinning

Form Quality

Hierarchy of Forms

Euhedral

Subhedral

Anhedral

Closed Forms

Dodecahedra

Octahedra

Disphenoids

Tetrahedra

Scalenohedra

Trapezohedra

Dipyramids

Open Forms

(Di)___Pyramids

Prisms

Pinacoids

Pedions

Constancy of interfacial angles

Bravais Principle

Techniques

Petrographic Microscope

X-Ray Microscope

XRD

Full Spectrum

Monochromatic

Powder

Crystal

Electron Micrscope

TEM

EMPA

Back Scattered Electrons

Scanning Electron Microscope

Symmetry

Laws

Definition of a Crystal

Quasicrystals existence lead to a new definition. It is a crystal if it has an essentially sharp diffraction pattern