410 likes | 605 Views
Minerals. Chapter 2. Matter. Matter includes anything that has mass and takes up space (volume). It exists in 3 main states on Earth – solid, liquid, and gas. Matter can be classified based on its physical state, chemical composition & structure. Elements.
E N D
Minerals Chapter 2
Matter Matter includes anything that has mass and takes up space (volume). It exists in 3 main states on Earth – solid, liquid, and gas. Matter can be classified based on its physical state, chemical composition & structure.
Elements Elements are the building blocks of minerals. Elements cannot be broken down into a simpler substance. 95 naturally occurring elements Organized based on properties in the Periodic Table of Elements
Periods on the Periodic Table The periods are the rows on the periodic table. Elements in the same period have the same number of energy levels in their electron cloud.
Groups on the Periodic Table The groups are the columns on the periodic table. Elements in the same group have similar properties. The groups are also called families.
Atoms Basic atomic structure
Compounds Compounds form when two or more elements combine making a substance with different properties from the elements that make it. For example: Salt or sodium chloride
Why Do Atoms Form Compounds? Most atoms are not chemically stable by themselves. They form chemical bonds with other elements to become stable. Elements in Group 18 are chemically stable by themselves.
Activity Look at the mineral samples in the container. Record 3 ways they are similar. Record 3 ways they are different. Create 2 groups for the minerals. Explain why you put them into these 2 groups.
Minerals 1. Naturally occurring 2. Solid at Earth’s surface 3. Crystalline structure 4. Definite chemical composition 5. Inorganic… usually
Mineral Formation Minerals generally form in one of 4 different ways.
Crystallization from Magma • Elements combine to form minerals as magma cools. • Examples • Feldspar • Quartz • Muscovite (mica) • Hornblende
Precipitation • Water holds a lot of dissolved substances. • As it evaporates, it leaves behind many of these substances. • Changes in the temperature of the water may also cause minerals to form. • Examples • Calcite • Halite (salt)
Pressure & Temperature • Changes in temperature and pressure can cause minerals recrystallize or become unstable. • New minerals will form as a result. • Examples • Talc • Muscovite (mica)
Hydrothermal Solutions • Chemical reactions occur when hot water (100-300 C) comes into contact with minerals. • New minerals form as a result of these reactions. • Examples • Bornite • Chalcopyrite
Mineral Groups Minerals are placed in groups based on their composition.
Silicates • Most common • Made of silicon and oxygen • Example: garnet
Carbonates • 2nd most common • Contain carbon, oxygen, & at least one metal • Example: calcite
Oxides • Contain oxygen and at least one other element that is usually a metal • Example: corundum
Sulfates & Sulfides • Contain sulfur • Examples: • Gypsum • Galena
Halides • Contain a halogen from group 17 of the periodic table and another element • Examples • Halite • Fluorite
Native Elements • Only contain one element • Examples • Gold • Silver • copper
Properties of Minerals Minerals are identified based on a variety of physical and chemical properties.
Color Color is not a very reliable identifying property for a lot of minerals. Some minerals, like sulfur, can be easily identified based on color.
Streak • Use the white porcelain plate and the black plate to check the streak of a mineral. • Try it.
Luster How does the mineral reflect light? Is it metallic or nonmetallic? Is it glassy, pearly, silky, earthy, brilliant? Try it.
Crystal Formation • This can be difficult to determine. • Not all crystals are allowed enough room to grow and do not immediately show a well developed crystal structure.
Hardness Minerals tend to have a specific range of hardness. A variety of common materials are used to test a minerals hardness. The glass plate is one of them. Try it.
Cleavage • No…not that kind. • Let’s take a look.
Fracture • This is the opposite of cleavage.
Density Density can be used to determine the purity or identity of minerals. See pages 54-55 for a list of some common minerals and their properties.
Distinctive Properties • Some minerals have very distinctive properties that are unique to them. • Sulfur (smell) • Graphite (greasy feel) • Calcite (bubbles in HCl) • Magnetite (is magnetic)