Minerals

What is Earth made of?

Elements

What do rows reflect in the periodic table?

number of electron shells

What do columns reflect in the periodic table?

number of electrons in outer shell

What does the number stand for in the periodic table?

number of protons

What is the evidence revealing Earth composition?

Samples of rock and meteorites, seismic observations, astronomical measurements

Continental crust composition

felsic to intermediate composition

Ex: Granite, granodiordite

Ocean crust compoisiotn

mafic composition

Ex: Basalt

Mantle composition

ultramafic composition

Ex: peridotite, dunite

Core composition

primarily iron and nickel

Mafic

magnesium-ferric

rocks that are dark in color and are rich in magnesium and iron

felsic

Feldspar-Silica

igneous rocks that are rich in light elements like silica, aluminum, potassium, and sodium

8 most abundant in the crust

Oxygen (-2), silicon (+4), Aluminum (+3), Iron (+2,+3), Calcium (+2), Sodium (+1), Potassium (+1), Magnesium (+2)

What is a mineral?

A solid, natural inorganic substance that has an ordered internal structure with specific chemical composition

crystalline rock

Rock composed of visible or microscopic crystals

clastic rock

composed of pieces (clasts)

Mineral and elemental abundances

13 elements make up 99.5% of crust

elements have properties that let them form specific types of bonds and there are few types of mineral forming process

crystal form

external geometric shape of a crystal

reflects internal atomic arrangment

Cleavage

What we see when a mineral breaks along a specific plane or planes

Hardness

the ease with which a mineral can be scratched on a relative scale called Mohs hardness scale

Luster

the way light reflects off the surface of a mineral

key is between metallic and non-metallic lustres

Color and Streak

easily scraping a corner of the sample across a streak plate to make a streak to get its true color

Density

measure of the mass of a mineral per unit volume

effervescence

rapid escape of gas from a liquid which causes bubbling and fizzing

Habit

external shape in which an individual/multiple crystals naturally grow

Fracture

an irregular break

magnetisim

how its internal atomic structure and unpaired electrons respond to an external magnetic field

Macroscopic properties

Macroscopic properties of minerals reflect their atomic scale structure

Metallic bonds

many atoms share electrons

weakest type of bond

Ionic bonds

donation of electrons from one atom to another

cation: positively charged ion

anion: negatively charged ion

covalent

sharing of electrons between two atoms

most bonds are partially covalent and partially ionic

Natural diamond bonding in minerals

carbon atoms in diamond are covalently bonded to four other carbon atoms

mineral classification classes

based on anions or anionic complexes

advantages of mineral classification

determine class with chemical formula

minerals within each class have similar structure

Silicate tetrahedron

one Si atom surrounded by four O atoms

Silicate classification oxygen

because O only uses half of its charge to bond to Si, it can easily bond to other elements

pyroxene

large group of single chain silicate minerals commonly found in igneous and metamorphic rocks

amphibole

large group of double chain silicate minerals

Silicate ratio

as more tetrahedra are linked together, the Si:O ratio decreases

Isolated tetrahedra need more cations for charge balance

higher melting temperatures

pressure increases

more mafic rocks

lower melting temperatures

water content increasing

more felsic

felsic and mafic temperatures

felsic materials will melt at lower temperatures than mafic materials

different compositions have different melting temperatures

melt composition

varies with rock source

mantle melt composition

forms mafic magma

continental crust melt composition

forms felsic or intermediate magma