1. Which of these planets…is 1.The seventh planet from the sun? 2.An inner planet? A.Saturn B. Jupiter C.Uranus D.Earth P. Reardon 2008 – Based on “Science Starters” by T. Trimpe at http://sciencespot.net/

2. The answers are… 1.The seventh planet from the sun- 2.An inner planet- d. Earth c. Uranus

3. Minerals and their Properties Chapter 2, Section 2.2 & 2.3

4. Looking Back  Matter  Atomic Structure  Periodic Table

5. Let’s Review  What is Atomic Number?  Number of Protons in the nucleus.  What is an Isotope?  An atom with the same number of protons as its element but a different number of neutrons.  What are the differences between ionic, covalent, and metallic bonds?  Ionic is when atoms transfer electrons and turn into ions, covalent bonds share electrons, and metallic bonds deal with metals and a “sea of electrons”

6. Looking Ahead  Tomorrow we start our 2-day lab of mineral identification and properties. TEST NEXT WEEK! CHAPTERS 1 – 2, PLEASE STUDY!!

7. Chapter 2.2 & 2.3 Vocabulary  Mineral  Silicate  Silicon-oxygen tetrahedron  Streak  Luster  Crystal Form  Hardness  Mohs Scale  Cleavage  Fracture  Density PLEASE WRITE DOWN AND DEFINE AS WE GO ALONG!

8. Minerals What are some of them?

9. Introduction  Everything you use and see in life is some sort of combination of minerals.  What are some things that you use in your life that are made of minerals?  Some common examples of mineral use:  Pencil lead is made from graphite  Body powders use talc  Dentist drill bits have small pieces of diamond in them  Quartz in windows

10. Minerals  A mineral in earth science is NOT the same thing as a mineral in food!  A mineral is a naturally occurring, inorganic solid with an orderly crystalline structure and a definite chemical composition.  For something to be considered a mineral, it must have the following characteristics

11. Mineral Requirements  Naturally Occurring:  Natural geologic processes so synthetic gems do NOT count as a mineral!  Solid Substance:  Minerals must be solid at temperatures that are normal at Earth’s surface.  Orderly Crystalline Structure:  Atoms/ions are arranged in orderly and repetitive manners.  Opal is not a mineral!

12. Mineral Requirements  Definite Chemical Composition:  Most minerals are chemical compounds made of two or more elements. A few only have one element.  Generally considered inorganic:  Inorganic crystalline solids found in nature. Salt (halite) is a mineral, but SUGAR IS NOT because SUGAR IS ORGANIC (comes from sugar cane—a plant).  “Generally Organic” because sometimes animals (especially in oceans) secrete calcium carbonate from their shells and this is considered a mineral.

13. How Minerals Form  Form everywhere on earth under very different conditions.  Silicates form deep in the crust or mantle where pressures and temperatures are VERY HIGH.  Minerals known as carbonates form in warm, shallow ocean water.  Clay minerals form at Earth’s surface when existing minerals are exposed to weathering.  Others form when rock is exposed to pressure or temperature changes.

14. How Minerals Form  Four major processes by which minerals form:  Crystallization from Magma  Precipitation  Changes in pressure and temperature  Formation from hydrothermal solutions

15. Crystallization from Magma  Magma is molten rock.  Formed deep within the earth.  As magma cools, elements combine to form minerals.  First to form are minerals rich in iron, calcium, and magnesium.  As minerals continue to form, the composition of the magma changes.  Minerals rich in sodium, potassium, and aluminum form.

16. Bowen’s Reaction Series

17. Precipitation  Water in Earth’s lakes, rivers, ponds, oceans, and beneath its surface contains many dissolved substances.  When water evaporates, these substances can react to form minerals.  Changes in temperature can also cause minerals to precipitate out of water.  Precipitation means that it is left behind—drops out of solution.  Halite (salt) and limestone!

18. Pressure and Temperature  Some minerals (including talc and muscovite) form when existing minerals are subjected to changes in pressure and temperature.  Pressure increase can cause minerals to recrystallize while still solid.  Atoms simply rearrange.  Changes in temperature can make minerals unstable.  New minerals form.

19. Hydrothermal Solutions  Hydrothermal solutions are very hot mixtures of water and dissolved substances.  Temperatures between 100 and 300 degrees Celsius.  When solutions come into contact with other minerals chemical reactions happen that form NEW minerals.  Solutions cooling causes new minerals to form like quartz and pyrite.

20. Mineral Groups Sorting Minerals

21. Introduction  Over 3800 minerals have been named, and new ones are identified each year.  We only study the most abundant minerals in this class.  Common minerals, together with thousands of others that form on Earth, can be classified into groups based on their Composition.

22. Silicates  Two most abundant elements in Earth’s crust are oxygen and silicon.  Silicon and Oxygen combine to form a structure called the silicon-oxygen tetrahedron.  One silicon atom and 4 oxygen atoms.  Framework for EVERY SILICATE mineral.  Most silicates also contain other elements (except for pure quartz).

23. Silicates  The tetrahedra can join in a variety of ways.  Very strong bonds.  Olivine is made of millions of single tetrahedra.  Augite has the tetrahedra form chains.  Double chains of tetrahedra form in minerals like hornblende.  Provide clues about the conditions the mineral formed in.  Most silicates crystallize from magma as it cools.  Can form at the surface or deep underground.  Place of formation and chemical composition influence which silicates form.  Olivine crystallizes at 1200 degrees C, but quartz crystallizes at 700 degrees.  Clay minerals from from silicates exposed to weathering at the surface.

24. Carbonates  Second most common mineral group.  Carbonates are minerals that contain the elements carbon, oxygen, and one or more other metallic elements.  Calcite (CaCO 3 ) is the most common carbonate mineral.  Dolomite contains magnesium and calcium.  Both limestone and marble are rocks composed of carbonate materials.  Used in building in construction.

25. Oxides  Minerals that contain oxygen and one or more other elements, which are usually metals.  Some form as magma cools beneath Earth’s surface.  Others (like corundum) form when existing minerals are subjected to changes in temperature and pressure.  Corundum is an aluminum oxide.  Hematite forms when existing minerals are exposed to liquid water or to moisture in the air.  Hematite is one form of iron oxide.

26. Sulfates and Sulfides  Minerals that contain the element sulfur.  Sulfates form when mineral- rich waters evaporate and leave the minerals behind.  Gypsum  Anydrite  Sulfides form from thermal (hot-water) solutions.  Galena  Sphalerite  Pyrite

27. Halides  Minerals that contain halogen ions plus one or more other elements.  Halogens are elements from group 7A of the periodic table.  Fluorine, Chlorine  Halite (NaCl) is a common halide.  Fluorite (CaF 2 ) is also common and used in making steel.  Forms when salt water evaporates.

28. Native Elements  Group of minerals that exist in relatively pure form.  Gold (Au)  Silver (Ag)  Copper (Cu)  Sulfur (S)  Carbon (C)  Native forms of carbon are diamonds and graphite.  Form in hydrothermal solutions.  Gold Rush TV Show

29. Properties of Minerals What’s so special about minerals anyway?

30. Sorting Minerals by Traits Groups of 4 (Periods 1 & 3) Groups of 5 (Period 4)

31. Introduction  Minerals come in many different sizes, shapes, and colors.  Some minerals are harder to break than others, some reflect light differently, and some have different textures.  There are several different ways to identify and classify different minerals.

32. By Color  One of the first things you usually notice about a mineral.  Color is unique to certain minerals so this property is sometimes useful in mineral identification.  Small amounts of different elements can give the SAME MINERAL different colors.  Sapphires vs. Rubies  Even though color CAN BE USEFUL, it is not something that you can rely on by itself! Color can sometimes be misleading!  Pyrite vs. Gold

33. By Streak  Streak is the color of a mineral in its powdered form.  Obtained by rubbing a mineral across a streak plate.  Color may vary between mineral samples, but the STREAK WILL NOT!  Help see the difference between metallic and nonmetallic minerals.  Metallic minerals have dark, dense streaks.  Nonmetallic minerals do not have such streaks.

34. By Luster  Luster is used to describe how light is reflected from the surface of a mineral.  Minerals that have the appearance of a metal—regardless of their color—are said to have a metallic luster.  Nonmetallic lusters include:  Vitreous  Glassy  Pearly  Silky  Earthy  Adamantine  Sub-Metallic

35. By Crystal Form  Crystal form is the visible expression of a mineral’s internal arrangement of atoms.  Every mineral has a distinct crystal form.  When a mineral forms slowly and without space restrictions it will develop into a crystal with well formed faces—sides, top, and bottom.  But usually minerals form in cramped, smashed spaces and intergroup so you cannot see their crystal form easily.

36. By Hardness  One of the most useful properties to identify a mineral.  Hardness is a measure of the resistance of a mineral to being scratched.  This can be determined by rubbing the mineral against another mineral of known hardness—one will scratch the other unless they have the same hardness.  Geologists use a standard hardness scale called the Mohs Scale.  The Mohs scale consists of 10 minerals arranged from 10 (hardest) to 1 (softest).

37. By Hardness  Other objects can also be used to determine hardness.  Your fingernail has a hardness of about 2.5  Copper Penny has a hardness of about 3.5  Glass has a hardness of 5.5  So the mineral Gypsum, which has a hardness of 2, can be scratched by your fingernail!  Quartz has a hardness of 7, so it will scratch glass!  Diamond is the hardest mineral on Earth and can scratch anything (Mohls Level 10)

38. Mohs Hardness Scale

39. By Cleavage  In the atomic structure of a mineral, some bonds are weaker than others.  These weak bonds are paces where a mineral will break when it is stressed.  Cleavage is the tendency of a mineral to cleave, or break, along flat even surfaces.  Micas have the simplest cleavage—since they are weak in one direction they tend to cleave in flat sheets  Quartz has strong bonds in all directions, so it does not have cleavage but FRACTURES instead.  Cleavage can happen in more than one direction at a time; Halite has 3 cleavage directions!

41. By Fracture  NOT the same thing as cleavage.  Minerals that DO NOT show cleavage when broken are said to fracture.  Fracture is the uneven breakage of a mineral.  If minerals tend to break into smooth curves surfaces, they are said to have conchoidal fracture.  Fibrous Fracture  Irregular Fracture

43. By Density  Density is a property of all matter that is the ratio of an object’s mass to its volume.  D = m/v  Density of copper is 8.96 g/cm 3  So any sample of copper will have that density.  Most minerals will have a density between 2 and 5 g/cm 3  The density of a mineral is a COMMON VALUE and is therefore a good indicator of mineral identity.  Density tables will be given on tests, don’t feel like you have to memorize them all!

44. By Distinctive Properties of Minerals  Some minerals can be recognized by other distinctive properties.  Talc and Graphite have distinctive ‘feels’.  Talc is ‘soapy’  Graphite is ‘greasy’  Metallic minerals are easily shaped (think copper, gold, etc!)  Magnetite is magnetic!  Calcite will double print when you look through it!  This is called double refraction.  Sulfur’s streak smells like rotten eggs.  Carbonate minerals fizz when exposed to Hydrochloric Acid  Mineral Properties depend on the elements that compose the mineral (it’s composition) and its structure (how its atoms are arranged).

46. Let’s Review  What is a native element?  A group of minerals that exist in a relatively pure form.  What are the four ways minerals form?  From cooling magma, from changes in temperature and pressure, precipitating, and from hydrothermal solutions.  What is luster?  How light is reflected from the surface of a mineral.  Why is color a bad indicator for identifying a mineral?  Color is unique to some minerals, but often it is hard to distinguish on color alone.