Es 14e lecture_ch02

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Matter and Minerals

Chapter 2 Lecture

Jennifer ManganJames Madison University

Earth ScienceFourteenth Edition, Global Edition


• Definition of a mineral – Natural– Inorganic– Solid– Possess an orderly internal structure of atoms – Have a definite chemical composition

• Rock – any naturally occurring solid mass of mineral or mineral-like matter

Minerals: Building Blocks of Rocks


Rocks are Aggregates of Minerals


• Atoms– Smallest particles of matter

Atoms: Building Blocks of Minerals


• Nucleus – central part of an atom that contains – Protons – positive electrical charges – Neutrons – neutral electrical charges

• Electron shells – Surround nucleus – Contain electrons – negative electrical charges

Atomic Structure


Atomic Structure


• Atomic number– Number of protons in an atom’s nucleus.

• Ions– Positively or negatively charged atoms due to electron gain

or loss

Atoms


• Elements – Basic building blocks of minerals – Over 100 are known– Defined by their number of protons– Groups of the same type of atoms

Composition and Structure of Minerals


Periodic table of the elements


• Valence shell– An atom’s outermost shell

• Octet rule – Atoms gain, lose, or share electrons until their valence shells

have 8 electrons

• Chemical bond – Transfer or sharing of electrons to achieve full valence shell

Atomic Bonding


Atomic Bonding

• Ionic bond– Atoms bond together when oppositely charged ions attract


• Covalent bond– Sharing of a pair of electrons between atoms

Atomic Bonding


• Metallic bond– Packed metal atoms have valence electrons free to

move throughout the structure.

Atomic Bonding


• Physical properties of minerals – Habit – common crystal shape– Luster – appearance in reflected light– Color– Streak – color of mineral in powdered form – Hardness – ability to resist scratching or abrasion– Cleavage – tendency to break along planes of weak bonding

Minerals


Metallic Luster: Galena


Color

• Color can be unreliable due to variations.


Streak


Crystal Shape, or Habit: Pyrite


Hardness: Mohs Scale


Cleavage: Micas


• Physical properties of minerals – Fracture – random pattern of breakage– Specific gravity – mineral density– Tenacity – resistance to cutting, breaking, bending, and

deformation

Minerals


Conchoidal fracture


• Other properties– Taste– Smell– Elasticity– Malleability– Double refraction– Magnetism – Feel– Reaction with hydrochloric acid

Minerals


• Rock-forming minerals– Only a few dozen– Most abundant atoms in Earth’s crust are oxygen (46.6% by

weight) and silicon (27.7% by weight)

Mineral Groups


• Eight elements compose most rock-forming minerals:– oxygen (O),– silicon (Si),– aluminum (Al)– iron (Fe)– calcium (Ca)– sodium (Na)– potassium (K)– magnesium (Mg)

Mineral Groups


Composition of Continental Crust


• Rock-forming silicates – Most common mineral group – Contain the silicon-oxygen

tetrahedron • Four oxygen atoms

surrounding a much smaller silicon atom

• Combines with other atoms to form the various silicate structures

Mineral Groups


• Rock-forming silicates – Groups based upon tetrahedral arrangement

• Olivine – independent tetrahedra • Pyroxene group – tetrahedra are arranged in chains• Amphibole group – tetrahedra are arranged in double chains

Mineral Groups


Hornblende: An Amphibole



• Micas – tetrahedra are arranged in sheets – Two types of mica are biotite (dark) and muscovite (light)

• Feldspars – Three-dimensional network of tetrahedra

Mineral Groups



• Feldspars – most abundant group of minerals in Earth’s crust• Quartz – three-dimensional network of tetrahedra

Mineral Groups


Potassium feldspar


Rose Quartz


• Nonsilicate minerals – major groups– Oxides– Sulfides– Carbonates– Halides– Native elements

Mineral Groups


Common Nonsilicate Mineral Groups


• Mineral groups – Nonsilicate minerals

• Carbonates– A major rock-forming group– Found in the rocks limestone and marble

• Halite and gypsum are found in sedimentary rocks• Many have economic value

Minerals


• Renewable– Can be replenished in relatively short time spans

• Corn, wind, water, etc.

• Nonrenewable– Earth has fixed quantities

• Oil, aluminum, natural gas, coal

Natural Resources


• Mineral resources – Mineral resources are occurrences of useful minerals that

will eventually be extracted– Ore deposits are concentrations of metallic minerals that can

be mined at a profit – Economic factors may change and influence a resource

Natural Resources


Copper Mining

Es 14e lecture_ch02

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