Chapter 9 Minerals Section 1 What is a Mineral? Notes 9-1

What is a Mineral? Mineral: a natural, inorganic, crystalline solid Inorganic: not made of a living thing or the remains of a living thing Inorganic: not made of a living thing or the remains of a living thing Crystalline (crystal): natural solid with a definite internal structure Crystalline (crystal): natural solid with a definite internal structure Every mineral has a specific chemical make up; can be a element or compound Every mineral has a specific chemical make up; can be a element or compound Rocks are not minerals; minerals are not rocks Rocks are not minerals; minerals are not rocks Rocks are made up of various minerals and organic matter

What makes a mineral, a mineral? Must answer yes to four important questions 1. Is this substance made of inorganic material? 2. Does this substance occur naturally? 3. Is this substance a solid in crystalline form? 4. Does this substance have definite chemical composition?

Kinds of Minerals Rock-forming minerals Form the rocks of the earth’s crust Form the rocks of the earth’s crust 20 out of 3,000 different minerals are common 20 out of 3,000 different minerals are common These 20 make up the rock forming minerals 10 of these are so common, they make up 90% of the earth’s crust Quartz, orthoclase, plagioclase, muscovite, biotite, calcite, dolomite, halite, gypsum, and ferromagnesian minerals (olivine, pyroxene and amphibole) Quartz, orthoclase, plagioclase, muscovite, biotite, calcite, dolomite, halite, gypsum, and ferromagnesian minerals (olivine, pyroxene and amphibole) Minerals can be classified into two major groups Minerals can be classified into two major groups

Quartz Orthoclase feldspar (K-spar) Plagioclase feldspar Muscovite mica

Biotite mica Calcite Dolomite Halite

Gypsum Olivine Pyroxene - Augite Amphibole - Hornblende

Silicate Minerals All silicates contain silicon and oxygen Quartz is purely silicon and oxygen Quartz is purely silicon and oxygen Other minerals have one or more different elements attached to the silicon and oxygen Feldspars are the most common silicate minerals Feldspars are the most common silicate minerals Orthoclase feldspar has potassium (K) attached to Si and O Plagioclase feldspar has sodium (Na) or calcium (Ca)

Silicate Minerals Ferromagnesian minerals Rich in magnesium (Mg) and iron (Fe) Rich in magnesium (Mg) and iron (Fe) Include olivine, pyroxene, amphibole and biotite Include olivine, pyroxene, amphibole and biotite Silicate minerals make up 96% of earth’s crust Feldspar and quartz make up 50% of the crust

Nonsilicate Minerals 4% of the earth’s crust Minerals that do not contain silicon (Si) Minerals that do not contain silicon (Si) Six major groups of nonsilicates (p ) Carbonates (CO 3 ) Carbonates (CO 3 ) Halides (Cl or Fl combined with Na, K or Ca) Halides (Cl or Fl combined with Na, K or Ca) Native Elements (uncombined) Native Elements (uncombined) Oxides (O and some other element besides Si) Oxides (O and some other element besides Si) Sulfates (SO 4 ) Sulfates (SO 4 ) Sulfides (one or more elements with S) Sulfides (one or more elements with S)

Crystalline Structure Crystal: natural solid with a definite internal pattern If unrestricted, a mineral will naturally form into a single, large crystal If unrestricted, a mineral will naturally form into a single, large crystal However, most often in natural crystal are not unrestricted However, most often in natural crystal are not unrestricted Most form in tiny crystal shapes that must be seen with a microscope Shapes can be helpful in the identification of a mineral Shapes can be helpful in the identification of a mineral

Crystalline Structure Structure of silicate minerals always begins with the silicon-oxygen tetrahedron One Si to Four O Combined in many different ways to produce different minerals

Crystalline Structure Some to remember Mica: Mica: forms in sheets Quartz: Quartz: framework silicate Feldspar: Feldspar: framework silicate

Homework Key Terms & Sticky Note Reading Ch. 9