Minerals & Earth's Crust

MICRO-REALM 01

Elements vs Minerals

→

• Element: Pure single atom
• Mineral: Ordered compound
• Elements combine into minerals

MICRO-REALM 02

5 Criteria of a Mineral

• Naturally occurring & inorganic
• Definite chemical formula
• Ordered atomic structure

MICRO-REALM 03

Single-Element Minerals

AuCuC

• Gold, Silver & Copper
• Sulphur, Graphite, Diamond
• Uncombined native state

MICRO-REALM 04

Compound Minerals

O

Si

O

• 2 or more elements
• Quartz ($\text{SiO}_2$) & Calcite
• Over 4,000 known species

MICRO-REALM 05

Mineraloids (Amorphous)

• Lack crystalline lattice
• Opal & Volcanic glass
• Amber & Pearl (organic)

MICRO-REALM 06

Hot Magma Origin

• Basic source of all minerals
• Crystallizes as magma cools
• Coal & petroleum excepted

MICRO-REALM 07

Minerals vs Rocks

• Rock: Aggregate of minerals
• No fixed rock formula
• Granite = Quartz + Feldspar

MICRO-REALM 08

The Crustal Eight (98.6%)

• 8 elements = 98.59% weight
• O, Si, Al, Fe, Ca, Na, K, Mg
• Rest 90+ elements = 1.41%

MICRO-REALM 09

1. Oxygen (46.60%)

O · #146.60%

• #1 crustal element by weight
• 93.8% of crustal volume
• Bonds into oxides/silicates

MICRO-REALM 10

2. Silicon (27.72%)

Si 27.7%

• #2 element in crust
• Tetravalent metalloid
• O + Si = 74.3% of crust

MICRO-REALM 11

3. Aluminium (8.13%)

Al · #38.13%

• #1 most abundant METAL
• #3 element overall
• Forms SIAL & Feldspars

MICRO-REALM 12

4. Iron (5.00%)

5%

32%

• #4 in Crust (5.00%)
• #1 in WHOLE Earth (32.1%)
• Sank to core early

MICRO-REALM 13

5. Calcium & 6. Sodium

Ca 3.63%Na 2.83%

• #5 Calcium: 3.63% (Calcite)
• #6 Sodium: 2.83% (Plagioclase)
• Key alkali/alkaline cations

MICRO-REALM 14

7. Potassium & 8. Magnesium

K 2.59%Mg 2.09%

• #7 Potassium: 2.59% (Orthoclase)
• #8 Magnesium: 2.09% (SIMA)
• Completes top 8 list

MICRO-REALM 15

Minor & Trace (1.41%)

Ti · H · P · Mn
S · C · Ni (1.41%)

• Titanium (#9 · 0.44%)
• Hydrogen, Phosphorus, Sulphur
• Concentrated in ore veins

MICRO-REALM 16

Silica Tetrahedron ($\text{SiO}_4^{4-}$)

• 1 central $\text{Si}^{4+}$ ion
• 4 corner $\text{O}^{2-}$ ions
• Fundamental silicate brick

MICRO-REALM 17

Silicate Polymerization

• Isolated (Olivine) to Chains
• Sheets (Mica) to 3D (Quartz)
• Shared oxygen corners

MICRO-REALM 18

Mineral Chemical Bonds

COVIONMET

• Covalent: Strongest (Diamond)
• Ionic: Soluble (Halite)
• Van der Waals: Weak (Talc)

MICRO-REALM 19

Polymorphism

= C =

• Same formula, different lattice
• Diamond vs Graphite (C)
• Calcite vs Aragonite ($\text{CaCO}_3$)

MICRO-REALM 20

Isomorphism (Solid Solution)

Mg

↔

Fe

• Similar-sized ions swap
• $\text{Mg}^{2+} \leftrightarrow \text{Fe}^{2+}$ in Olivine
• Same crystal geometry

MICRO-REALM 21

Six Crystal Systems

• Cubic, Tetragonal, Hexagonal
• Orthorhombic, Monoclinic, Triclinic
• Internal symmetry axes

MICRO-REALM 22

Silicate Dominance (92%)

92%

• 92% of Earth's crust
• Feldspar (50%) + Quartz (12%)
• Primary rock-forming group

MICRO-REALM 23

Felsic vs Mafic Silicates

FELSIC

MAFIC

• Felsic: Light, K/Na/Al, SIAL
• Mafic: Dark, Mg/Fe, SIMA
• Low vs High specific gravity

MICRO-REALM 24

Oxide Minerals

Fe₂O₃

• Metal bonded with Oxygen
• Hematite & Magnetite (Fe)
• Bauxite & Corundum (Al)

MICRO-REALM 25

Carbonate Minerals

CaCO₃

• Built on $\text{CO}_3^{2-}$ ion
• Calcite & Dolomite
• Forms Limestone & Marble

MICRO-REALM 26

Sulphides & Sulphates

FeS₂

• Sulphides: Pyrite, Galena (Pb)
• Chalcopyrite (Cu), Sphalerite
• Sulphates: Gypsum & Barite

MICRO-REALM 27

Halides & Phosphates

• Halides: Halite ($\text{NaCl}$), Fluorite
• Evaporite salt basins
• Phosphates: Apatite (teeth/bones)

MICRO-REALM 28

Bowen's Reaction Series

• Magma crystallization order
• First (Hot): Olivine, Ca-Plag
• Last (Cool): Quartz, Muscovite