class work watch the video clip and answer the following questions: 1. how did we know about the...

Class Work

• Watch the video clip and answer the following questions:1. How did we know about the earth’s interior for so

long?

2. What did scientists begin to use to understand the center of the earth?

3. What do seismic waves measure?

4. What is the inner core made up of?

5. What does the inner core generate for planet Earth?

What is a Mineral?

• Naturally-formed solid substance with a specific chemical & crystal structure

Pyromorphite

What do all minerals have in common?

All:1. Are inorganic. Are NOT alive and NEVER were

alive

2. Are formed by natural processes.

3. A crystalline solid that has a definite volume and shape. Are made up of particles that are arranged in a pattern that is repeated over and over (called a CRYSTAL)

4. Are elements or compounds with a unique chemical makeup

Groups of Minerals

• Minerals are grouped by the elements they are made of.

Amethyst

Beryl (Emerald) Calcite

Mineral Group Characteristics Examples

Silicates

Contain oxygen & silicaThe most abundant group of minerals

Quartz (SiO2), mica

MICA Quartz

Mineral Group Characteristics Examples

Non-Silicates

Make up only 4-5% of the Earth’s crustInclude some of the most important minerals

iron, copper, gold, silver, diamonds, rubies

Silver

GoldRuby Iron

Copper

Diamond

Mineral Group Characteristics Examples

Carbonates Carbon & oxygen and a positive ion, such as calcium

Calcite (CaCO3)

Calcite with Duftite inclusions

Mineral Group Characteristics Examples

Oxides Metallic ion and oxygen

Hematite (Fe2)O3

Mineral Group Characteristics Examples

Sulfides Sulfur and a metallic ion

Galena (PbS)

Mineral Group Characteristics Examples

Halides Chlorine & fluorine combined with sodium, potassium or calcium

Halite (NaCl)Fluorite (CaF2)

Mineral Group Characteristics Examples

Sulfates Metallic ion, Sulfur & oxygen

Barite (BaSO4)

Barite on Calcite BaSo4 / CaCO3

BariteBaSo4

Mineral Group Characteristics Examples

Native Elements

Single elements

Gold (Au), Diamond (C), Silver (Ag)

How do minerals form?

• 1) Cooling of magma (hot, liquid rock and minerals inside the earth (from the mantle))– Fast Cooling = No Crystals (mineraloids)–Medium Cooling = small crystals– Slow Cooling = large crystals

How do minerals form? Evaporites

• 2) form when elements & compounds remain behind when water evaporates. Dissolved in liquids: usually water. (Think of rock candy.)

Physical Properties of Minerals (can be used to identify the mineral)

Color• Can be misleading• Can vary with the type of impurities

Physical Properties of Minerals (can be used to identify the mineral)

Luster• Surface reflection • metallic = shiny like

metal• non-metallic = dull,

earthy, virteous, non-shiny surface

Pyrite has a metallic luster

Calcite has a non-metallic luster

Luster Characteristics• Adamantine - very gemmy crystals • Dull - just a non-reflective surface of any kind • Earthy - the look of dirt or dried mud • Fibrous - the look of fibers • Greasy - the look of grease• Gumdrop - the look a sucked on hard candy• Metallic - the look of metals • Pearly - the look of a pearl• Pitchy - the look of tar • Resinous - the look of resins such as dried glue or chewing gum Silky - the

look of silk, similar to fibrous but more compact Submetallic - a poor metallic luster, opaque but reflecting little light

• Vitreous - the most common luster, it simply means the look of glass • Waxy - the look of wax

Physical Properties of Minerals (can be used to identify the mineral)

Streak• The color of the powdered form of

the mineral• The color of the streak can be

different than the mineral• Minerals must be softer than the

streak plate

Streak…can help identify quartz

http://www.childrensmuseum.org/geomysteries/cube/b3.html

Physical Properties of Minerals (can be used to identify the mineral)

Hardness• How easily a mineral scratches materials• Mohs Hardness Scale

• Scale from 1 (softest) to 10 (hardest)• Test by seeing if the mineral can scratch different

objects (like human fingernail, copper, penny, glass, steel file)

Physical Properties of Minerals (can be used to identify the mineral)

Cleavage & Fracture– The way the mineral breaks– Cleavage—minerals break along

smooth, flat surfaces and every fragment has the same general shape

– Fracture—minerals that break at random with rough or jagged edges

Cleavage or Fracture?

1.

4.

3.

2.

Minerals: More Characteristics

• Taste (ex. Halite)• Fluorescence (ex. Fluorite)• Phosphorescence (ex. Willemite)• Radioactivity (ex. Uraninite)• Double refraction (ex. Calcite)• Magnetism (ex. Magnetite)• Reactivity to acids (ex. Calcite)

Physical Properties of Minerals (can be used to identify the mineral)

Other Properties– Specific gravity (*excellent clue to mineral’s

identity)– Attraction to magnets– Bending of light– Reaction with hydrochloric acid– Smell & taste

http://www.childrensmuseum.org/geomysteries/cube/b4.html

Giant Crystal Caves

• http://www.youtube.com/watch?v=wgUFb_l4DLE

Watch Identifying Minerals Clip

Answer the following questions in your notebook…

1. How many minerals have scientists discovered?

2. Of them only _______ are the most common minerals.

3. What is the composition of the rock Basalt? (This makes up the dense oceanic crust.)