Chapter 13 Minerals Courtesy of Tiffy75 at SlideShare

What Is A Mineral? A mineral is a naturally formed, inorganic solid with a crystalline structure. Is It A Mineral? It might be, if you can answer yes to the following questions: Is it a solid? Is it formed in nature? Is it nonliving material? Does it have a crystalline structure? http://www.flickr.com/photos/mheisel/2936798136/

Is It A Solid? Minerals can’t be gases or liquids! No Air & No Water

Is It Formed In Nature? Crystalline materials made by people aren’t classified as minerals. No Man Made Gemstones & No Tires

Is It Nonliving Material? A mineral is inorganic, meaning it isn’t made of living things. No Teeth & No Bones

Does It Have A Crystalline Structure? Minerals are crystals, which have a repeating inner structure that is often reflected in the shape of the crystal. Minerals generally have the same chemical composition throughout. www.rblewis.net/.../WebQuests/atoms/atoms.jpg

Does It Have A Crystalline Structure? Let’s break it down: Minerals are made up of Elements Elements are pure substances that can’t be broken down into simpler substances Atoms are the smallest part of an element Mineral Element Atom

Does It Have A Crystalline Structure? More than one type of atom stuck together is a compound Most minerals are made up of compounds of different atoms Sodium + Chlorine Halite z.about.com/d/chemistry/1/0/Y/6/halite.jpg

Does It Have A Crystalline Structure? When atoms are held in a set structure it is called a crystal (or a crystalline structure) http://www.flickr.com/photos/alishav/3221701134/ 9

Two Types of Minerals Minerals that contain Silicon and Oxygen Silicate NonSilicate Minerals that contain Silicon and Oxygen 90% of Earth’s crust is made up of Silicate Minerals Examples: Feldspar, Biotite Mica & Quartz Minerals that do not contain Silicon & Oxygen Examples: Native copper, Gold, Diamond, Calcite, Fluorite and Galena. mrbarlow.files.wordpress.com/2009/02/diamond.jpg

Identifying Minerals Now that you know your sample is a mineral… we need to learn how to identify what mineral it is Properties to ID Minerals Color Luster Streak Cleaving & Fracture Hardness Density Special Properties

Identifying Minerals: Color Not a good indicator for ID Example: Pyrite (Fool’s Gold) has a golden color normally – but when exposed to weather for a long time it turns black www.3dchem.com/imagesofmolecules/pyrite2.jpg

Identifying Minerals: Luster Luster is the way a surface reflects light Example: Dull or Shiny Types of Luster: Metallic ( Shines like metal) Submetallic (Metallic but dull) Nonmetallic (glassy, silky, Pearly, earthy, waxy) Add picture from p. 64 www.thunderhealing.org/rock/anglesite.jpg 13

Identifying Minerals: Streak Streak is the color of a mineral’s powdered form More reliable than Color because weathering doesn’t change the Streak Color geology.csupomona.edu/alert/mineral/streak.jpg

Identifying Minerals: Cleaving & Fracture Minerals break in certain ways depending on how the atoms are arranged Cleaving: When minerals break along flat surfaces Ex. Diamonds and Rubies Fracture: When minerals break unevenly or irregularly Ex. Quartz

Identifying Minerals: Hardness Hardness refers to a mineral’s resistance to being scratched Example: Diamond is the hardest mineral, Talc is the softest mineral. Moh’s Hardness Scale: Scale 1 – 10 (1 softest, 10 hardest) z.about.com/.../1/0/W/A/1/magnetitemassive.jpg

Identifying Minerals: Density Density is how much matter there is in a given amount of space (Mass/Volume-- unit-grams/cubic centimeter )1mL=1cm3) Density of Water: 1 g/cm3 Specific Gravity =Object’s Density/Density of Water The specific gravity of an unknown mineral can tell you its identity

Identifying Minerals: Special Properties Some minerals have unique properties: Taste (ex. Halite) Fluorescence (ex. Calcite & Fluorite) Chemical Reaction (ex. Calcite) Optical Properties (ex. Calcite) Radioactivity (ex. Radium & Uranium can be detected in a mineral) Magnetism (ex. Magnetite & Pyrrhotite)