Minerals Chapter 3 Lesson 1 p.142

Before we get started… There are a few things we need to know before we get into minerals element- a pure substance that cannot be broken down into simpler substances by ordinary chemical means Atom- smallest unit of an element that maintains the properties of that element Molecule- stable particles made up of strongly bonded atoms Compounds- molecules of 2 or more elements

What is a mineral? Mineral- a naturally occurring, usually inorganic solid that has a definite crystalline structure & chemical composition

What Do Minerals Have in Common? Definite Chemical Composition Solid Usually Inorganic Crystalline Structure Naturally Occurring

Definite Chemical Composition Determined by the element or compound that makes up the mineral Native Element: minerals composed of only 1 element Ex: Gold or Silver Quartz is a compound where silicon atoms have bonded with oxygen atoms in a repeating pattern

Solid State of Matter Matter- anything that takes up space; has volume and mass Volume: amount of space that is taken up Mass: the amount of matter in an object Weight: Gravitational pull on an object Solids –Liquids – Gases What is ice?

Usually Inorganic Is not made up of living things or the remains of living things. Most minerals are inorganic

Crystalline Structure Minerals have a crystalline structure because they have crystals Crystal- solid, geometric form that results from a separating pattern of atoms or molecules. Crystal shape is produced by the arrangement of atoms or molecules & the conditions under which it forms Can be placed into crystal classes based on their shape

Naturally Occurring Minerals formed from natural processes Examples: Water Evaporating Water Cooling Rock Cooling High Temperature & Pressure

How Are Minerals Formed? Minerals form within Earth or on Earth’s surface As Magma & Lava are cooled By Metamorphism From Solution

Cooling Magma / Lava Many minerals come from magma As magma cools, atoms join together to form minerals Same applies to lava Example: Quartz

Metamorphism Temperature & pressure cause new minerals to form as bonds break and atoms create new bonds with different atoms Ex: Diamonds, Graphite

Solutions When water evaporates, substances in water are left behind & form solids Ex: Gypsum Hot water is able to dissolve more materials than cold water As hot water cools, substances can form solids that precipate out of a solution Ex: Dolomite

How Are minerals Classified? Most common mineral classification is based on chemical composition Silicates Nonsilicates

Silicate Minerals Minerals that contain a combination of silicon and oxygen Silicon & oxygen are 2 of the most common elements found in Earth’s crust Obviously Silcate minerals make up most of Earth’s crust. Examples: Quartz, Feldspar (silicate tetrahedron) Examples: Mica, Olivine (silicate tetrahedron combined w/ other elements)

Nonsilicate Minerals Elements that do not contain a silicate tetrahedron These minerals can be made up elements such as sulfur, carbon, iron, fluorine, & even oxygen A nonsilcate mineral’s chemical composition determines its class.

What Properties Can Be Used To ID Minerals? Color Streak Luster Cleavage or Fracture Density Hardness Special Properties

Color The same minerals can have different colors Vice Versa So color is a good start to identification, but not enough on its own

Streak Streak- The color of the powdered form of a mineral Found by rubbing a mineral against a white tile Called a streak plate Not always the same color as the mineral Streak is not affected by water or air More reliable than color for ID’ing a mineral

Luster Luster- the way surface reflects light Metallic Nonmetallic Silky Pearly Earthy Waxy Shiny Resinous Glassy

Cleavage or Fracture Cleavage- tendency of a mineral to split along specific planes of weakness to form smooth, flat surfaces Flake like breaks Many minerals do not break along these weaknesses Some fracture or break unevenly Uneven breaking is called a fracture

Hardness A mineral’s resistance to being scratched Mohs Hardness scale used to measure hardness The greater the mineral’s resistance to being scratched – the greater its hardness rating If the reference mineral scratches your mineral , the reference mineral is as hard or harder than your mineral

Density Is the measure of how much matter is in a given amount of space. Measure in grams per cubic centimeter g/cm3 Gold can be ID’ed from pyrite this way

Special Properties All minerals exhibit the 6 properties we just went over Some minerals have extra properties such as: Magnetism Double Image Ultraviolet