MINERALS CH. 2

The building blocks of minerals are elements. MINERALS

An element is a substance that cannot be broken down into simpler substances by chemical or physical means. CHEMISTRY AND MINERALS

Atom-The smallest particle of matter that contains the characteristics of an element. Parts of an Atom: Neutron Proton Electron CHEMISTRY AND MINERALS CONT…

Protons Positively Charged Found in the nucleus. # of protons=atomic number Neutron No charge Found in the nucleus. Has the same mass as protons. PROTONS AND NEUTRONS

Negatively charged Located in energy levels surrounding the nucleus. 1/1836 the mass of a proton. ELECTRONS

Atoms with the same number of protons, but different numbers of neutrons. ISOTOPES

A compound is a substance that consists of two or more elements that are chemically combined in specific proportions. Chemical Bonds are the forces that hold atoms together in a compound. BONDING

TYPES OF BONDS IonicCovalentMetallic Transfer of electronsSharing of electrons between two atoms Sharing of electrons between metal ions. Metal and NonmetalNonmetal and NonmetalMetals and Metals Table Salt (NaCl)Water or SugarAlloys (Brass)

Minerals are naturally occurring, inorganic solids with an orderly crystalline structure and definite chemical composition. MINERALS!!!!

1.Crystallization from Magma 2.Precipitation 3.Pressure and Temperature 4.Hydrothermal Solutions HOW MINERALS FORM

As magma cools, elements combine to form minerals. Crystal structure depends on the rate of cooling and pressure. First to crystallize: Rich in iron, calcium, and magnesium. Second to crystallize: Rich in sodium, potassium, and aluminum. CRYSTALLIZATION

Water evaporates, some dissolved substances can react to form minerals Two common examples Limestone and Halite PRECIPITATION

An increase in pressure can cause minerals to recrystallize while still solid. Changes in temperature can also cause certain minerals to become unstable and rearrange into a configuration that is more stable at the new conditions. Common Examples: Muscovite and Talc PRESSURE AND TEMPERATURE

Hot mixture of water and dissolved substances. Temps. Between °C When they come into contact with existing minerals, chemical reactions take place to form new minerals. Examples: Chalcopyrite, bornite, and pyrite HYDROTHERMAL SOLUTIONS

MINERAL GROUPS Common minerals can be classified into groups based on their composition. Silicates Carbonates Oxides Sulfates/Sulfides Halides Native Elements

The most common group of minerals on Earth. Silicon and oxygen combine to form a structure called the silicon-oxygen tetrahedron. Examples: Micas, Olivine, Quartz, and Hornblende SILICATES

2 nd most common mineral group. Carbonates are minerals that contain the elements carbon, oxygen, and one or more other metallic elements. Examples: Calcite, Dolomite CARBONATES

Oxides are minerals that contain oxygen and one or more other elements, which are usually metals. Examples: Corundum and hematite OXIDES

Sulfates and sulfides are minerals that contain the element sulfur. Examples: Pyrite, Galena, Sphalerite SULFATES/SULFIDES

Halides are minerals that contain a halogen ion plus one or more other elements. Examples: Halite and fluorite HALIDES

Native elements are a group of minerals that exist in relatively pure form. Example: Gold, Silver NATIVE ELEMENTS

Color Streak Luster Crystal Form Hardness Cleavage Fracture Density *Other Distinctive Properties PROPERTIES OF MINERALS

Color not usually helpful in identifying a mineral. Streak The color of a mineral in its powdered form. PROPERTIES OF MINERALS

Luster: how light is reflected. Metallic: shiny Nonmetallic: earthy, silky, or glassy Crystal Form visible expression of a mineral’s internal arrangement of atoms. Well-developed crystals form slowly and without space restrictions. PROPERTIES OF MINERAL

Hardness The measure of the resistance of a mineral to being scratched. Mohs Hardness Scale: consists of 10 minerals arranged form 10 (hardest) to 1 (softest) PROPERTIES OF MINERALS

Cleavage: The tendency of a mineral to cleave, or break, along flat, even surfaces. Fracture: Uneven breakage. PROPERTIES OF MINERALS

Density: Mass/volume Pure minerals have constant densities. PROPERTIES OF MINERALS

Texture/Feel Talc feels soapy. Magnetism Magnetite is magnetic Smell Sulfur has a rotten egg smell. Acid Reaction Calcite reacts with HCl DISTINCTIVE MINERAL PROPERTIES