Rocks & Minerals Review

Minerals

• Definite chemical composition

• Inorganic

• Solid

• Crystalline

• Occur naturally

Mineral Properties

• Hardness

– Moh’s Scale of Hardness 1-10

– Hardness is the resistance to being scratched

– Find by attempting to scratch minerals with

materials of a known hardness (like your

fingernail 2-2.5 or glass 5.5-6)

Mineral Properties

• Streak = color of powder

– Find by rubbing mineral against a ceramic

streak plate to create powder

• Luster = shine from unweathered surface

– Metallic (shiny like metal)

or non-metallic (dull or

glassy)

Mineral Properties

• Cleavage = breaks along smooth, parallel

sides

• Fracture = uneven breaking surfaces

• Breaking pattern depends on atomic

arrangement of mineral and if zones of

weakness exist

Fracture Cleavage

Rock Cycle

• 3 rock types are

igneous,

sedimentary, and

metamorphic.

• Any rock can

change into any

other rock type.

Sedimentary Rocks

• Form due to compaction and cementation

of rock particles

• Divided into 3 groups based on formation:

– Clastic (from other rock pieces)

– Chemical / Crystalline (from solution)

– Bioclastic (from organic materials)

Sedimentary Rocks

• Observable Characteristics:

– Layers of sediments (strata)

– Visible sediments (sand,

pebbles)

– Fossils or shells

– Chemical sedimentary rocks

are composed of only one

mineral (like rock salt from

halite)

Igneous Rocks

• Form when molten rock cools and hardens

• 2 types based on location of formation:

– Intrusive (plutonic): form underground

• cool slowly; large crystals (coarse-grained)

– Extrusive (volcanic): form above ground

• cool quickly; small or no crystals (fine-grained or

glassy)

• Mafic or Felsic based on composition

Igneous Rocks • Observable

Characteristics

– Glassy

– Vesicular texture (gas pockets)

– Interconnected mineral crystals (usually more than one color—like granite)

– Multiple mineral composition

Metamorphic Rocks

• Form due to heat and pressure (recrystallization)

• 2 types based on texture

– Foliated: mineral crystals are aligned (banding is when minerals separate into stripes)

– Non-foliated: interconnected mineral crystals

• 2 types of metamorphism

– Regional: large area of heat and pressure due to plate collision

– Contact: small area of heat due to hot fluids

Metamorphic Rocks

• Observable

Characteristics

– Foliation (minerals

flatten and line up)

– Banding (stripes of

minerals)

– Intergrown mineral

crystals (like marble)

– Foliated mica

– Garnets

Earth Science Reference Tables

• Page 6: Rock Cycle

• Page 6: Igneous Rock Chart

• Page 7: Sedimentary Rock Chart

• Page 7: Metamorphic Rock Chart

• Page 16: Properties of Minerals

Which rock type and why?

• Sedimentary

(chemical)

• Halite, gypsum

• Made of only one

mineral

Which rock type and why?

• Igneous (intrusive)

• Andesite, pegmatite

• Interconnected

mineral crystals

• Multiple mineral

composition

Which rock type and why?

• Sedimentary (clastic)

• Conglomerate

• Pebbles visible

Which rock type and why?

• Metamorphic

• Gneiss

• Foliated

• Banding

• Stripes of crystals

• NOT layers

Which rock type and why?

• Igneous (intrusive)

• Granite

• Interconnected

mineral crystals

• Multiple mineral

composition

Which rock type and why?

• Sedimentary

(bioclastic)

• Coquina

• Made of shell

fragments

Which rock type and why?

• Igneous (extrusive)

• Scoria, pumice

• Vesicular

• Gas pockets/holes

Which rock type and why?

• Metamorphic

• Schist

• Foliated mica

• Foliated

Which rock type and why?

• Metamorphic

• Quartzite, marble

• Interconnected

mineral crystals

Which rock type and why?

• Sedimentary (clastic

or bioclastic)

• Fossils

Which rock type and why?

• Sedimentary (clastic)

• Sediments (sand

grains) visible

• Layers of sand

• Strata

Which rock type and why?

• Igneous (extrusive)

• Obsidian

• Glassy

Answer = quartz

Answer = 4

Answer = talc

What is each rock type?

1 = sedimentary

2 = igneous

3 = metamorphic

A diagram shows a beach and the paragraph

mentions that the headlands are made of diorite

bedrock.

Answer = 2

Answer = 3

Answer = 4

Answer = 4

Answer = rock salt; crystallizes from solution

Answer = 1

The reading states ―the limestone rock lining the

seafloor underwent metamorphism as it was

pushed deep into Earth‖

Answer = marble