AIM:

What is the difference

between a rock and a

mineral? What are the

properties of minerals?

DO NOW: What is the difference

between lemon juice and lemonade.

Notepack # 14 November 15, 2016

Introduction – Comparing Minerals to Rocks

• Mineral

– Naturally occurring

– Inorganic

– Characteristic chemical composition

– Ordered atomic structure

– Specific physical properties

• Rock

– Naturally occurring

– Can be organic

– Can have multiple chemical compositions

– Physical properties can change

– Composed of minerals

What are Minerals? • Minerals are substances that

are pure and are made of only one kind of molecule.

• Minerals have unique properties that do not change when it is under pressure or heat.

• Minerals have 6 major properties or characteristics: Luster, Color, Streaking, Hardness, Crystal Structure, and Cleavage.

Minerals Properties

• Properties of Minerals

– Luster • The way light reflects off a

mineral

• Metallic

– Looks like metal

• Non-Metallic

– Doesn’t look like metal

– Can still be shiny

Mineral Properties

• Color – Not a great way to

identify minerals

– A mineral’s color can change considerably • Rose Quartz vs. regular

Quartz vs. green quartz

• Red Hematite vs. Silver Hematite

– Many minerals have the same color • Halite and Calcite can

both be clear

Mineral Properties

• Streak

– The color of the powdered form

– A mineral’s color can change but streak will typically remain the same

Mineral Properties

• Hardness

– Resistance to scratching • Harder minerals will

scratch softer minerals

– Measured on Moh’s Hardness scale • 1 – soft

– Talc

• 10 – Hard

– Diamond

Mineral Properties

• Crystal Structure

– Many minerals have a characteristic shape • Ex:

– Diamond

– Galena

– Calcite

– Halite

Mineral Properties

• Cleavage

– How a mineral breaks

– A minerals shows cleavage if it breaks: • evenly

• with a specific shape

• with flat sides

• Fracture

– Opposite of cleavage

Minerals

• Gemstone

– Precious or semi-precious stone

– Valuable due to color, luster, hardness….

– Some gemstones are rocks, but most are minerals

What are Rocks?

• Rocks are formed as a results of the combination of minerals they have in them.

• Rocks are classified by how they are formed.

• Unlike minerals, rocks can change into other rocks if under pressure and heat.

Categories of Rock

• Rocks are separated into 3 categories:

– Igneous rock – new rock that is form straight from the mantle.

– Sedimentary rock – rock that is produced as the result of the weathering or erosion of old rock which piles up on itself.

– Metamorphic rock – rock the change as the results of extreme heat and pressure.

Igneous Rocks

• Volcanic Rocks

– Form from solidification or cooling of: • Lava

– Liquid rock on earth’s surface

• Magma

– Liquid rock inside the earth

Types of Igneous Rocks • Intrusive

– Form inside the earth

– Solidify slowly

– Allows mineral crystals time to grow • Shows large mineral

grains (crystals)

Types of Igneous Rocks

• Extrusive – Forms on the earth’s

surface

– Cools quickly

– Doesn’t allow crystals time to form

– Can show a glassy texture • Can be shiny, but doesn’t

have to be

• Glassy simply means no crystals whatsoever

Types of Igneous Rocks

• Vesicular

– Forms from lava that’s being disturbed

– Gas is bubbling out of the lava

– Rock shows gas pockets (holes)

Sedimentary Rocks

• Form different ways, but most are associated with:

– Weathering, erosion, deposition with water

Types of Sedimentary Rocks

• Clastic Sedimentary Rocks

– Contains pieces of other rocks

– Form when other rocks become weathered, eroded, and then the pieces are cemented together

Types of Sedimentary Rocks

• Chemical Sedimentary Rocks (Crystalline)

– Forms when minerals are left over after seawater evaporates

Metamorphic Rocks

• Form when other rocks undergo heat and pressure

– Called metamorphism

– Results in a recrystallization of rocks • Can have mineral crystals

like igneous rocks

Types of Metamorphic Rocks

• Foliated

– Crystals have been re-arranged in bands or layers

– Can look like cleavage planes • But remember only

minerals show cleavage, not rocks

Types of Metamorphic Rocks

• Non-Foliated

– No bands/layers

– Can be difficult to tell a non-foliated metamorphic rock from igneous rock

The Rock Cycle

• Rocks are classified by how they form

• Any rock can turn into any other rock

• The Rock Cycle Chart shows how rocks form and change over time