Chapter 3: AtomS, Elements, Minerals, Rocks: Earths Building Materials
Chapter 3: Atoms, Elements, Minerals, Rocks: Earth’s Building Materials
Introduction: What Is a mineral a Mineral Naturally formed, inorganic, solid material with a specific chemical composition and a characteristic crystalline structure. Rock Naturally formed coherent mass of one or more minerals, sometimes including organic debris
◼ Mineral ◼ Naturally formed, inorganic, solid material with a specific chemical composition and a characteristic crystalline structure. ◼ Rock Naturally formed, coherent mass of one or more minerals, sometimes including organic debris. Introduction : What Is A Mineral?
Key Characteristics of minerals a minerals have two key characteristics Composition The chemical elements that compose a mineral and their proportions. a Crystal structure. The organized way in which the atoms of the elements are packed together in a mineral
Key Characteristics of Minerals ◼ Minerals have two key characteristics. ◼ Composition: ◼ The chemical elements that compose a mineral, and their proportions. ◼ Crystal structure: ◼ The organized way in which the atoms of the elements are packed together in a mineral
Composition of Minerals a few minerals are composed of a single element(diamond, graphite, gold, copper, and sulfur a Most minerals are compounds, containing more than one element a Chemical elements are the most fundamental substances into which matter can be separated by chemical means
Composition of Minerals ◼ A few minerals are composed of a single element (diamond, graphite, gold, copper, and sulfur). ◼ Most minerals are compounds, containing more than one element. ◼ Chemical elements are the most fundamental substances into which matter can be separated by chemical means
Crystal Structure of minerals The atoms in most solids are organized in regular, geometric patterns, called the crystal structure. Solids that have a crystal structure are said to be crystalline Ice in a glacier meets the definition of a mineral Solids that lack crystal structures are amorphous glass and amber
Crystal Structure of Minerals ◼ The atoms in most solids are organized in regular, geometric patterns, called the crystal structure. ◼ Solids that have a crystal structure are said to be crystalline. ◼ Ice in a glacier meets the definition of a mineral. ◼ Solids that lack crystal structures are amorphous. ◼ glass and amber
Crystal form a Crystal: any solid body that grows with planar surfaces. a The interfacial angle in any crystalline structure remains constant
Crystal Form ◼ Crystal: any solid body that grows with planar surfaces. ◼ The interfacial angle in any crystalline structure remains constant
regular Growth of Quartz grains
Iregular Growth of Quartz grains
Fibers of Chrysotile Asbestos
Fibers of Chrysotile Asbestos
Growth Habit and Polymorphism a growth habits The characteristic crystal form of each mineral a Polymorphism: Some elements and compounds form two or more different minerals: C Graphite, Diamond Ca CO3 Calcite, Aragonite Fes rite, Marcasite白铁矿 SiO2 Quartz, Cristobalite方英石
Growth Habit and Polymorphism ◼ Growth habit: ◼ The characteristic crystal form of each mineral. ◼ Polymorphism: ◼ Some elements and compounds form two or more different minerals: ◼ C Graphite, Diamond ◼ CaCO3 Calcite, Aragonite ◼ FeS2 Pyrite, Marcasite 白铁矿 ◼ SiO2 Quartz, Cristobalite 方英石
Cleavage Cleavage is the tendency to break in preferred directions along bright, reflective planar surfaces. aa cleavage surface is a breakage surface, whereas a crystal face is a growth surface The planar directions along which cleavage occurs are governed by the crystal structure. They are planes along which the bonding between atoms is relatively weak
Cleavage ◼ Cleavage is the tendency to break in preferred directions along bright, reflective planar surfaces. ◼ A cleavage surface is a breakage surface, whereas a crystal face is a growth surface. ◼ The planar directions along which cleavage occurs are governed by the crystal structure. ◼ They are planes along which the bonding between atoms is relatively weak
