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Elements & Minerals
GLG 101 - Physical Geology
Bob Leighty
These notes and web links are your primary “lecture” content in this class.
Additionally, various articles are assigned each week to supplement this “lecture”
information. I believe you’ll have enough information to reference without having
to purchase a costly textbook.
These lecture notes are very similar to the ones I use in my traditional classes.
You’ll find they are loaded with imagery and streamlined text that highlight the
most essential terms and concepts. The notes provide a framework for learning
and, by themselves, are not meant to be a comprehensive source of information.
To take advantage of the global knowledge base known as the Internet, I have
included numerous hyperlinks to external web sites (like the Wikipedia, USGS,
NASA, etc.). Follow the links and scan them for relevant info. The information
from linked web sites is meant to supplement and reinforce the lecture notes –
you won’t be responsible for knowing everything contained in them.
As a distance learning student, you need to explore and understand the content
more independently than in a traditional class. As always, I will help guide you
through this learning adventure. Remember, email Dr. Bob if you have any
questions about today’s lecture ([email protected]).
Leave no questions behind!
Explore and have fun!
Elements
and Minerals
Rocks, Minerals, & Elements
 Rocks  Minerals  Atoms
Elements
and Minerals
Rocks, Minerals, & Elements
 Rocks = a collection of one or more minerals
 Minerals = a collection of one or more elements (atoms)
rocks
minerals
granite
quartz + feldspar + biotite
atoms
quartz =
silicon + oxygen
Elements
and Minerals
What’s in an Atom?
 Nucleus
> protons = dense particles, (+) electrical charge
> neutrons = dense particles, neutral electrical charge
 Electrons = light particles, (-) electrical charge
Elements
and Minerals
It’s Elemental
 An element is the word used for separating different types of
atoms (H, O, C, etc.)
 The # of protons in the nucleus determines the type of atom
(element)
> an atom with 6 protons = the element carbon
> all C atoms have 6 protons
> all K atoms have 19 protons
> all U atoms have 92 protons
Elements
and Minerals
It’s Elemental
Isotopes
 In any element, the number of neutrons can vary
6 protons & 6 neutrons: mass number = 12
=
12C
6 protons & 7 neutrons: mass number = 13
=
13C
6 protons & 8 neutrons: mass number = 14
=
14C
 These variations of the same element are called isotopes
Elements
and Minerals
Atomic Building Blocks
 There are 117 known elements (as of 2006), but only 92 occur
naturally
Earth’s
Crust
Elements
and Minerals
Atomic Bonding
Ions
 When atoms gain or lose e-, they become ions
Na loses an e- & becomes
a (+) charged ion (Na+)
Cl gains an e- & becomes a
(-) charged ion (Cl-)
Elements
and Minerals
Atomic Bonding
 Bonding of atoms is largely determined by the # of electrons in
the outermost electron shell of an atom
A water molecule
O
H
Salt water
H
Elements
and Minerals
Atomic Bonding
Elements
and Minerals
Atomic Bonding
Ionic
 Atoms “loan” electrons
 Bonds are weak (e.g., soluble in water)
Example: Rock salt - Sodium (Na) and Chlorine (Cl)
Elements
and Minerals
Atomic Bonding
Covalent
 Atoms “share” electrons
 Bonds are strong
Example: Diamond (C)
Elements
and Minerals
Making Minerals
 Minerals are the combination of one or more elements
> Occur naturally (not manmade)
> Inorganic
> Orderly internal structure
> Definite chemical composition
Elements
and Minerals
Rock-forming Minerals
Concept Maps
 Graphical summaries that
show relations between
various terms and concepts
Click here for more examples of concept maps
Click on the image to see a larger version.
Elements
and Minerals
Rock-forming Minerals
Silicates
 Basic building blocks: 1 Si + 4 O = a silica tetrahedron
 Combine other elements (e.g., Mg, Fe, Al, etc.) with different
arrangements of silica tetrahedra
O2Si4+
O2-
O2O2-
Elements
and Minerals
Rock-forming Minerals
Silicates
isolated
tetrahedra
single
chains
double
chains
sheets
3-D
frameworks
Elements
and Minerals
Rock-forming Minerals
Carbonates
 Basic building blocks: 1 C + 3 O
calcite
Elements
and Minerals
Rock-forming Minerals
Sulfides
Sulfides
Oxides
Native
elements
Halides
Carbonates
Silicates
Elements
and Minerals
Physical Properties of Minerals
Elements
and Minerals
Physical Properties of Minerals
Luster
 How a mineral reflects light
Elements
and Minerals
Physical Properties of Minerals
Hardness
 Resistance to scratching
Elements
and Minerals
Physical Properties of Minerals
Cleavage
 Planes of weakness in a mineral
mica
calcite
Elements
and Minerals
Physical Properties of Minerals
Color
 Largely dependant on composition
Quartz
Amethyst (purple quartz)
Smokey quartz
Elements
and Minerals
Physical Properties of Minerals
Streak
 The color of a mineral when powdered
Hematite displaying a reddish streak
Elements
and Minerals
Physical Properties of Minerals
Specific Gravity
 Density of a mineral relative to water (1.0 g/cm3)
higher (10-20 g/cm3)
lower (2-3 g/cm3)
Elements
and Minerals
Physical Properties of Minerals
Crystal Form
 Unique forms controlled by a mineral’s atomic structure
Elements
and Minerals
Physical Properties of Minerals
Others
 magnetism
 effervescence
 fluorescence
 Crystal striations
Elements
and Minerals
WWW Links in this Lecture
> Rocks - http://en.wikipedia.org/wiki/Rock
> Minerals - http://en.wikipedia.org/wiki/Mineral
> Atoms - http://en.wikipedia.org/wiki/Atom
> Element - http://en.wikipedia.org/wiki/Chemical_element
> Nucleus - http://en.wikipedia.org/wiki/Atomic_Nucleus
> Protons - http://en.wikipedia.org/wiki/Protons
> Neutrons - http://en.wikipedia.org/wiki/Neutrons
> Electrons - http://en.wikipedia.org/wiki/Electrons
> Isotopes - http://en.wikipedia.org/wiki/Isotopes
> Periodic Table of the Elements - http://en.wikipedia.org/wiki/Periodic_Table
> Ion - http://en.wikipedia.org/wiki/Ion
> Electron Shell - http://en.wikipedia.org/wiki/Electron_shell
> Ionic bond - http://en.wikipedia.org/wiki/Ionic_bond
> Halite - http://en.wikipedia.org/wiki/Halite
> Covalent bond - http://en.wikipedia.org/wiki/Covalent_bond
> Diamond - http://en.wikipedia.org/wiki/Diamond
> Concept maps - http://en.wikipedia.org/wiki/Concept_maps
> http://www.mc.maricopa.edu/dept/d43/glg/Study_Aids/concept_maps/conceptmaps.html
Elements
and Minerals
WWW Links in this Lecture
> Silicate - http://en.wikipedia.org/wiki/Silicate
> Silicate minerals - http://en.wikipedia.org/wiki/Silicate_minerals
> Carbonate - http://en.wikipedia.org/wiki/Carbonate
> Sulfide - http://en.wikipedia.org/wiki/Sulfide
> Sulfate - http://en.wikipedia.org/wiki/Sulfate
> Oxide - http://en.wikipedia.org/wiki/Oxide
> Halide - http://en.wikipedia.org/wiki/Halide
> Physical properties - http://en.wikipedia.org/wiki/Minerals#Physical_properties_of_minerals
> Luster - http://en.wikipedia.org/wiki/Lustre
> Mineral hardness - http://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardness
> Cleavage (crystal) - http://en.wikipedia.org/wiki/Cleavage_%28crystal%29
> Streak - http://en.wikipedia.org/wiki/Streak_%28mineralogy%29
> Crystal form - http://en.wikipedia.org/wiki/Crystal_structure
> Magnetism - http://en.wikipedia.org/wiki/Magnetism
> Effervescence - http://en.wikipedia.org/wiki/Carbonation
> Fluorescence - http://en.wikipedia.org/wiki/Fluorescence