Minerals: We walk on them, we wear them, we wash our clothes with them, we may even brush our teeth with them. They bring electricity into our lives and provide the building materials for our homes and schools. Without minerals, we would not have an Earth!
|Banded Iron Formation - Australia
To understand what these materials are, that are an integral portion of our life:
As citizen's of the Earth, and as students of geology.
To provide a solid foundation in conceptual aspects of mineralogy:
What minerals are, how they form, how they are analyzed and described, how they behave as a function of P-T-X, how they are classified, identified, and utilized.
To understand their utility in the study of our Earth:
Because these materials are the products of complex Earth and Planetary processses that occur over a wide range of temperatures and pressures, minerals can tell us conditions of formation and subsequent evolution of the continents and ocean basins.
Pallasite meteorite, photo courtsey of the Smithsonian Institution
To provide linkages to other areas of geology:
petrology, geochemistry, geophysics, structural geology, meteoritics, environmental geology, geomicrobiology, economic geology
Recent and fossilized pinecones
To connect with other fields of study:
inorganic chemistry, material science, gemology, soil science, biology, nanoscience, art, archeology
Uxelite, a mineral that behaves as a fiber optic
To understand their central role in our standard of living,
Have fun learning how the Earth works!
We will apply principles learned from each portion of the course as we proceed......
Lecture material concentrates on concepts and principles
Lab exercises put these principles to use where we descibe and identify hand specimens
Mineralogy & MINERALS
| Mineralogy, or Mineral
Science, is the study of minerals.
- crystallography (where we'll start)
- how chemical elements make minerals
- crystal chemistry
- relates chemical composition, internal structure, and
- physical properties
- geologic occurrence
- how and where they form
We are all familiar with minerals
|We are all familiar with Minerals
diamond in matrix
||White, Black, Green, Pink
|Mud after a rainstorm
Minerals are the building blocks of the EARTH!
|Basic units from which rocks
and everything else in the Earth are comprised
Metamorphic rocks, Campolungo, Switzerland
|Minerals as Key Components
||Different minerals form in
different geologic environments.
| Essential to our standard
||- from our ancestors (fire,
arrowheads) to today's superconductors
we depend on terrestrial raw materials for everything that makes our life above subsistence level
|e.g. metals (Cu, Au, Ag), diamonds,
or store important reserves: oil, gas
Native Copper in Veins - AZ
|Each year, every American requires 40,000 lbs
of new minerals!
||Can the world sustain this
rate of consumption?
||Massive Sulfides, Czech Republic
|They provide solutions to environmental
||e.g. Absorbants - Zeolites,
Clay minerals (kitty liter)
- Retard migration of toxic chemicals
|They cause some environmental
||acid mine drainage, asbestos,
We'll develop a feel for the diversity of minerals and their behavior in a wide variety of environments
One of the unifing themes of mineralolgy is that
of crystal chemistry; the elucidation of the relationship between chemical composition, internal structure and physical
||formed by natural processes
synthetic = lab made
||excludes liquids and gases
||highly ordered atomic arrangement,
an internal structural framework of atoms (ions) arranged in a regular,
repeating, geometric pattern (periodic)
solids that lack an ordered atomic arrangement are amorphous
|definite chemical composition
||definite but not fixed, within
limits (or range) of compositions and can be expressed as a chemical formula:
|formed by inorganic processes,
||it is increasingly recognized
that minerals may be produced organically e.g. magnetite in bird brains,
aragonite in shells = biomineralization
plagioclase feldspar, labradorite, Madagascar
There are ~ 4200 known mineral species.
This is minor compared to the biological world; there are more than 10,000 species of inchworms alone!
|| mineral-like but lack all
the qualifications (opals)
|Naming of minerals
||after properties, place, people
|quartz - SiO2||opal|
WHAT IS A ROCK?
|Aggregrate of grains
|made of one or more minerals
Granite Slab - Sardinia
| The study of rocks is PETROLOGY.
Epidote and Quartz, Madagascar
|Rock||Not a rock|
|Began with mineral's Uses
||Minerals and rock were selected
and used for certain purposes
long before humans even devised a written language.
|The prehistory of humanity
is dated by the materials with which our predecessors made their tools.
| One of our first scientific
acts was to distinguish between different rocks and minerals and use them as tools according to their properties.
|"Stone and the Stone
|Our early ancestors were vegetarians,
when their ancestors became omnivorous, the use of tools was essential.
|Realized suitibility of certain
e.g. obsidian and flint became widely used.
| Fire was started
by striking pyrite with flint.
Naturally-occurring poisons such as arsenic were known and used.
|Toward the end of the Neolithic,
ca. 40 different rocks and minerals were in use.
|"Metals and the Bronze Age"
|Naturally occurring native metals
were greatly sought after by Stone age humanity
for their curiosity and ornamental value rather than for tool making.
Discovered that heating metals greatly promotes
the ease with which they can be worked and extracted.
|Metals have been used for at
least 4000 yrs; prehistoric man was also known to mine and smelt metallic minerals to produce Au,
Ag, Fe, Cu, Pb and bronze.
e.g. Hg was in use in Egypt as early as the 15th-16th C BC and
the old Testament of the Bible refers to the use of Au, Ag, Cu, Sn, Pb and Fe.
| About 1400 B.C.
|Fe is hard, durable and abundant|
| Throughout the Stone, Bronze
and Iron ages, humanity also began to use an increasing number of
minerals unrelated to the manufacture of tools.
||Fascination with ART seems an
intrinsic property of the human psyche.
Cave art is our earliest record.
| Colored pigments became common;
red and black pigments (hematite and pyrolusite, Mn oxides)
were used for cave painting for over 5000 yrs.
|Other minerals (jade, amethyst,
garnet) were used for ornamentation or the diverse
hard minerals and rocks
used for tools and weapons (jade, flint, obsidian).
* Indian, 1100 B.C.
* First written work on minerals
is by Greek philosopher Theophrastus
(372-287 B.C.) and Pliny 300 yrs later.
* Emergence of mineralogy as a science
is credited to German physican
Georgius Agricola with the publication De Re Metallica in 1556.
* 1669 Steno and his law.
Interfacial angles of quartz xls are constant, no
matter what the size and shape of the crystal is.
This discovery lead to the science of crystallography.
He was beatified in 1988 by the pope
* followed by the physics of minerals
century, rapid advances with the
development of instruments which could measure
precisely angles between xl faces.
* the chemistry on minerals.
1854 Dana introduced the chemical classification used today.
e.g. bk. After J.D. Dana...
* 20th century,
- 1914 Braggs solved the first crystal structure.
* Now rapid advances in instrumentation
and techniques for measuring and imaging
exact positions of atoms in a crystal.
Linus Pauling, the Nature of the Chemical Bond
1. CRYSTALLINE - characteristic of a mineral; long range 3D internal structural order
2. CRYSTAL - when external form is bounded by geometric forms
- external form is function of growth environment and may not reflect internal order.
We use term
in broader sense to indicate ordered 3D structure.
|Staurolite, Urals, Russia|
3. Crystal GROWTH
- grow from nucleus by accretion from soln, melt or vapor
- grow from outside cf. plants
amount of space available for growth determines shape
4. MORPHOLOGY - external form of mineral
(a) euhedral = well formed faces
(b) subhedral = partial xl faces
(c) anhedral = no xl faces
(d) microcrystalline = xls observable
|Tiger's Eye, Australia (SiO2 replaced Amphibole)|
(e )cryptocrystalline = xl resolved with x-rays
(f) amorphous = no long range order
5. CRYSTALLOGRAPHY - study of crystalline materials
crystal symmetry, orientation of atoms in xl.
(a) direct imaging of internal arrangement e.g. TEM
(b) relationship between xl faces - symmetry
Two methods to describe positions of atoms in xline matter:
(a)Translational - spatial relationships
(b)Rotational - relationships between