Earth Composition

Question 1

What is a crystal?

Answer 1

A solid with a highly ordered atomic structure forming a repeating crystal lattice in all directions

Question 2

What is a mineral?

Answer 2

A naturally occurring, inorganic, solid substance with a definite chemical composition and ordered atomic arrangement

Question 3

What is a mineraloid?

Answer 3

A naturally occurring inorganic solid lacking a crystal structure, e.g., obsidian or opal

Question 4

What is crystallography?

Answer 4

The study of the arrangement and bonding of atoms in crystalline solids

Question 5

What is a crystal lattice?

Answer 5

A 3D structure formed by repeating units of atoms, ions, or molecules in a crystal

Question 6

What is a unit cell?

Answer 6

The smallest repeating unit in a crystal lattice that defines the crystal’s structure

Question 7

What are the 7 crystal systems?

Answer 7

Cubic, Tetragonal, Orthorhombic, Hexagonal, Trigonal, Monoclinic, Triclinic

Question 8

What are Bravais lattices?

Answer 8

The 14 possible 3D lattice types combining crystal systems with unit cell types

Question 9

What are the 4 unit cell types?

Answer 9

Primitive (P), Body-centered (I), Face-centered (F), Side-centered (C)

Question 10

What is polymorphism in minerals?

Answer 10

The ability of a chemical compound to crystallize in more than one structure

Question 11

What is isostructuralism?

Answer 11

Different minerals with different compositions sharing the same crystal structure

Question 12

What is isomorphism?

Answer 12

A complete solid solution between two minerals with similar structures but different compositions

Question 13

What type of bond is found in halite?

Answer 13

Ionic bond

Question 14

What is a homodesmic mineral?

Answer 14

A mineral with only one type of chemical bond throughout its structure

Question 15

What is a heterodesmic mineral?

Answer 15

A mineral with multiple types of chemical bonds in its structure

Question 16

What types of bonds can occur in minerals?

Answer 16

Ionic, covalent, metallic, and Van der Waals

Question 17

What type of bond is strongest in minerals?

Answer 17

Covalent bonds

Question 18

What does geochemistry study?

Answer 18

The origin, distribution, and evolution of chemical elements in Earth’s crust

Question 19

What are lithophiles?

Answer 19

Elements that bond with oxygen and form rock-forming minerals

Question 20

What are siderophiles?

Answer 20

Elements that bond with iron and are found in the core

Question 21

What are chalcophiles?

Answer 21

Elements that bond with sulfur and form sulfide minerals

Question 22

What are atmophiles?

Answer 22

Elements that are associated with the atmosphere

Question 23

What defines mineral classification?

Answer 23

The dominant anion or anionic group in the mineral’s structure

Question 24

What are native element minerals?

Answer 24

Minerals composed of a single element, such as gold or copper

Question 25

What are sulfides?

Answer 25

Minerals where metals bond with sulfur, often ore-forming

Question 26

What are oxides?

Answer 26

Minerals with oxygen bonded to metal elements

Question 27

What are halides?

Answer 27

Minerals formed from halogen elements like F-, Cl-, Br-, and I-

Question 28

What are carbonates?

Answer 28

Minerals containing the CO3^2- group, common in marine environments

Question 29

What are phosphates?

Answer 29

Minerals with the PO4^3- group, found in biological and volcanic contexts

Question 30

What are sulfates?

Answer 30

Minerals with the SO4^2- group, often formed through evaporation

Question 31

What are silicates?

Answer 31

The most abundant mineral class, formed from silicon-oxygen tetrahedra

Question 32

What is the basic structural unit of silicates?

Answer 32

The SiO4^4- tetrahedron

Question 33

What is polymerization in silicates?

Answer 33

The sharing of oxygen atoms between silica tetrahedra

Question 34

What are nesosilicates?

Answer 34

Silicates with isolated tetrahedra, e.g., olivine, garnet

Question 35

What are sorosilicates?

Answer 35

Silicates with paired tetrahedra, e.g., epidote

Question 36

What are cyclosilicates?

Answer 36

Silicates forming rings of tetrahedra, e.g., beryl, tourmaline

Question 37

What are inosilicates?

Answer 37

Chain silicates: single (pyroxenes) or double (amphiboles) chains

Question 38

What are phyllosilicates?

Answer 38

Sheet silicates like micas and clays

Question 39

What are tectosilicates?

Answer 39

Framework silicates with all tetrahedra fully polymerized, e.g., quartz and feldspars

Question 40

What is a solid solution in minerals?

Answer 40

A mineral structure where different elements substitute for each other

Question 41

What is coupled substitution?

Answer 41

Element replacement involving a second substitution to preserve charge balance

Question 42

What is the Si:O ratio in quartz?

Answer 42

0.043055555555555625

Question 43

What role does aluminum play in silicates?

Answer 43

It can substitute for silicon in tetrahedra or fill octahedral sites

Question 44

What is the significance of feldspars in the crust?

Answer 44

They are the most abundant group of tectosilicates

Question 45

What are alkali feldspars?

Answer 45

Feldspars with K and Na, like orthoclase, microcline, and albite

Question 46

What are plagioclase feldspars?

Answer 46

A series between albite (Na) and anorthite (Ca) feldspars

Question 47

What is the formula for muscovite?

Answer 47

KAl2(AlSi3O10)(OH)2

Question 48

What is the difference between dioctahedral and trioctahedral sheets?

Answer 48

Dioctahedral sheets have two occupied octahedral sites, trioctahedral have three

Question 49

What are examples of trioctahedral phyllosilicates?

Answer 49

Talc and biotite

Question 50

What are examples of dioctahedral phyllosilicates?

Answer 50

Kaolinite and muscovite