Monday November 02, 2009 Open your notebooks. Write down today’s questions.

Today’s Theme: What is a mineral?– What are the ways that minerals can be identified?– What defines whether something is a mineral or not?– What is a crystal?– What is the difference between a rock and a mineral?

Hand in any late work Progress Reports Tomorrow (Due Thursday) Science Fair Complete Write Up Due Friday!!!!!!!!! OMG

MineralsToday: Use your keen powers of observation to

make a list in your notebook of all of the physical properties you notice about the six samples.

Think about these questions:– Are they all minerals?– Why do they look the way they do?– How did they form?– What are they composed of?– Where did they come from?

Thursday November 05, 2009

Please write today’s lesson and date written in your notebook.– Today’s lesson: Properties of Minerals

• What are the physical properties of minerals?• How do we tell minerals apart?

New Red Books Open to Page 70

Please do not touch equipment yet!!!!

Progress Reports Due TODAY (signed by parent)

Science Fair Complete Write Up is due Tomorrow.

Properties of Minerals Learning Objectives

– What are the ways that minerals can be identified?

– What is Moh’s Hardness Scale?

– What is the difference between cleavage and fracture?

– What are some common uses for minerals?

What is a mineral?

A mineral is– Naturally Occurring (made by earth-not man made),– Inorganic (never was alive),– Solid (atoms in fixed position, definite volume/shape),– with a definite crystal structure (repeating pattern of

minerals atoms),– and a definite chemical composition (same elements

throughout in a certain proportion)

Which of these are minerals?Which of these are minerals?Which of these are minerals?Which of these are minerals?AMBER COAL

PEARL

SUGAR

QUARTZ

HALITE

MICA

Salesite

Gold

Fluorite

Tiptopite (clear) & Montgomeryite

Acanthite

Asbestos

Gypsum

Pyrite

Feldspar

Physical Properties of Minerals

These properties are used to identify minerals

1. Color

Color is the most noticeable physical property of a mineral but is THE LEAST reliable.

This is because the same mineral can come in many colors.

Example:

Mineral IdentificationMineral Identification

rhodochrosite malachite turquoise

azuriteColor is one physical property that can beused to identify minerals but beware……

The many colors of Calcite

The many colors of Quartz

Streak:The color of the powdered form of a mineral when

rubbed on an unglazed porcelain plate

StreakThe mineral is rubbed on an unglazed

porcelain plate to determine the color of the streak powder.

Not all minerals have a streak. Any mineral harder than the plate (7+) will leave a scratch instead.

Streak Example: Same Mineral!

3. LusterLuster describes how light is reflected from a

mineral’s surface.

A mineral has either – Metallic Luster (shines like a metal) or – Non-Metallic Luster.

• Dull, earthy, waxy, greasy, pearly, silky or vitreous (glassy)

Luster:

The mineral The mineral Galena has a Galena has a metallic lustermetallic luster

Metallic Luster Non-Metallic Luster

Examples of Luster

Metallic or Nonmetallic?

Metallic or Nonmetallic?

Metallic or Nonmetallic?

Density

Density is the comparison of mass to volume.– It’s really how well packed are the atoms in the

object.

Mass divided by volume

5. HardnessHardness is a measure of how easily a mineral

is scratched.

– determined by arrangement of the mineral’s atoms.

Mohs Hardness Scale:a relative scale used to determine the mineral’s hardness

Fingernail Penny Iron Nail Glass Streak Plate

2.5 3.5 4.55.5

6.5

Crystal Systems

The way the mineral grows atom by atom makes a shape we call a crystal.– Most of the time you can’t see them.– More time and space it had to grow = bigger

crystals

Crystal FormsThese are Quartz

CrystalsThese are These are Quartz CrystalsQuartz Crystals

Texture Texture describes how a mineral feels to the touch. Texture can be described as greasy, soapy, glassy,

rough, ragged or smooth. Graphite has a greasy texture.

Cleavage or Fracture Cleavage - When Minerals break along planes

(layers) where bonding between atoms is weak.

A mineral that splits or breaks easily along smooth, flat surfaces is said to have cleavage.

•Mica has perfect cleavage in one direction (plane).

•Halite has cubic cleavage (3 planes).

Three Examples of Perfect Cleavage – Fluorite, Halite & Calcite

Cleavage of Minerals

Cleavage

Cleavage or Fracture

Minerals that break along rough, jagged or uneven edges and surfaces are said to have fracture.– conchoidal (shell-like), splintery, uneven, jagged or

earthy

Conchoidal Example :Quartz

Don’t be confused between Crystal Faces (sides) and Cleavage Planes! - Both minerals in these pictures show Fracture (not cleavage)

These are These are Quartz CrystalsQuartz Crystals

These are These are Quartz CrystalsQuartz Crystals

Special Properties

Specific gravityReaction to acidStriations (lines)MagnetismFluorescence

Uses of MineralsGems or Gemstones are highly prized minerals

because they are rare and beautiful.An Ore is a mineral that contains a useful

substance that can be mined at a profit.

Ore Name Gives Us

Hematite Iron

Chalcopyrite Copper

Bauxite Aluminum

Sphalerite Zinc

Uses of MineralsUses of MineralsGems: Gems: Valuable Valuable minerals minerals prized for prized for rarity and rarity and beauty.beauty.

Ores: Ores: Minerals that Minerals that can be mined can be mined at a profit.at a profit.

Gems: Gems: Valuable Valuable minerals minerals prized for prized for rarity and rarity and beauty.beauty.

Ores: Ores: Minerals that Minerals that can be mined can be mined at a profit.at a profit.

Uses of Minerals http://www.minsocam.org/MSA/K12/uses/uses.html

http://www.emporia.edu/earthsci/amber/go336/talkingt/

The Copper Queen Mine in Bisbee, AZ

An Underground Halite Mine

Birthstones January Garnet or Rose Quartz February Amethyst or Onyx March Aquamarine or Bloodstone April Diamond or Quartz Crystal May Emerald or Crysoprase June Alexandrite or Moonstone or Pearl July Ruby or Carnelian August Peridot or Sardonyx September Sapphire or Lapis October Opal or Tourmaline November Topaz or Citrine December Tanzanite, Zircon or Turquoise

History of Birthstones In early times, gemstones were believed to possess magical

properties. Some minerals were thought to contain a force or hold certain values and powers.

Tradition associates a gem with each sign of the zodiac based on a color system. Color was thought to unleash the power attributed to the stone.

The Roman, Arabic, Jewish, Polish, Russian and Italian birthstone lists were all different.

In time, birthstones became associated with calendar months rather than the zodiac.

And people began to select birthstones in colors other than the original.

This list of birthstones, which is the one commonly used today, was adopted in 1912 by the American National Association of Jewelers, which later evolved into the Jewelers of America.

Mineral Compositions and Groups

Minerals are grouped based on their chemical composition (the elements that make up the minerals).

Almost 98% of the Earth’s crust is made of only 8 common elements (O, Si, Al, Fe, Ca, Na, K, Mg).

Silicon (Si) and Oxygen (O) are the most common elements in the Earth’s crust.

Major groups are….(In order of size)• Silicates (Si, O) (Largest rock forming group)

• Carbonates (CO3)

• Oxides (O3, O4)

• Sulfides (SO4)

• Sulfates (SO3)

• Halides (F, Cl, I, Br)

• Hydroxides (OH)2

• Phosphates (PO3)

• Native Elements (Au, Ag, Cu)

Mineral Compositions and Groups

Mineral Compositions and GroupsMineral Compositions and Groups

Examples of SilicatesHornblende

Examples of SilicatesOrthoclase Feldspar

Examples of SilicatesPlagioclase Feldspar

Carbonates

Sulfates

Halides

Native ElementCopper