Where Do Minerals Form?

Minerals to Know: (formation and identifiable characteristics)

QuartzHalitePyriteMica

◼ Quartz and Mica

◼ Quartz –white/colorless streak

◼ Mica – forms in 3 ways

◼ Magma cools as it moves toward the crust forming small crystals - Plutons

Mica

Quartz

◼ Halite

◼ Cubic crystal

◼ Tastes like Salt

◼ NaCl

◼ Evaporation:

◼ Water evaporates and leaves mineral crystals

Halite

◼ Pyrite

◼ Fool’s Gold

◼ Black Steak

◼ Composed of Leadand Sulfur

◼ Ground water sinks into the mantle; mixes with minerals and forms a metal crystal

Pyrite

◼ Magma/Inside the Earth

◼ Extreme heat and pressure change an existing mineral into a new one –Metamorphic Mineral

Mica

Properties of

Minerals

How Are Minerals Identified?

◼ Color

◼ Luster

◼ Hardness

◼ Streak

◼ Cleavage and Fracture

◼ Special Properties

Color◼ Usually the first and most easily observed

◼ The color minerals appear in normal light

-Some minerals are always the same color

-Some minerals can have many colors

QUARTZROSE QUARTZ SMOKY QUARTZ

Luster

◼ General appearance of a mineral surface in reflected light

Glassy-Obsidian

Hardness◼ Resistance to scratching by different items; “scratchability”

Moh’s Mineral Hardness Scale

1) Talc

2) Gypsum

3) Calcite

4) Flourite

5) Apatite

6) Feldspar

7) Quartz

8) Topaz

9) Corundum

10) Diamond

Softest

Hardest

1

2

3

4

5

6

7

8

9

10

Streak

◼ The color of the minerals fine powder

◼ Determined by rubbing the mineral on a piece of unglazed porcelain (streak plate)

Cleavage & Fracture◼ The tendency of a mineral to split or crack along flat edges

◼ 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.

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

Other Properties (Only Unique to certain minerals)◼ Attraction to magnets

◼ Fluorescence

◼ Reaction with hydrochloric acid

◼ Smell & taste

Rocks

Rock Cycle

Know these rocks

◼ Igneous: Scoria and Obsidian

◼ Sedimentary: Shale and Coquina limestone

◼ Metamorphic: Marble, Quartzite, and Schist

Rocks

▪ Naturally Occurring

▪ Solid

▪ Made of two or more different minerals that have been:

◼cemented together

◼squeezed and heated together

◼melted and cooled together.

Igneous Rocks

◼ Igneous rocks are produced by the cooling and hardening of magma and lava.

◼ Origin:

◼ Intrusive

◼ Extrusive

◼ Texture:

◼ Coarse-grain

◼ Fine-grain

◼ No grain

◼ Composition:

◼ Felsic – light colors; High silica (sand)

◼ Mafic – dark colors; Low silica (sand)

Composition

◼ Extrusive- Formed from lava; volcanic

◼ Intrusive- Formed from magma deep within the earth

Obsidian Pumice

Granite

Scoria

Textures

◼ Glassy No-Grain

◼ Fine-grained

◼ Coarse-grained

Obsidian Granite

Basalt

Scoria

Sedimentary Rocks◼ Formed from the breaking apart of other rocks (igneous,

metamorphic, or sedimentary rocks)

◼ Steps to Formation

◼ Erosion

◼ Deposition

◼ Compaction

◼ Cementation

◼ Composition

◼ Clastic

◼ Chemical

◼ Organic

Classification of Sedimentary Rocks

◼ Clastic Rocks- Made of the fragments of previously existing rocks

◼ Organic Rocks- Come from organisms

◼ Chemical Rocks- Formed by inorganic processes such as evaporation

Clastics Rocks◼ Conglomerate

◼ Sandstone

◼ Mudstone

Organic Rocks

◼ Limestone

Coquina Fossiliferous Limestone

Chemical Rocks

◼ Limestone

Chalk Limestone

Pentamerous Limestone

Metamorphic Rocks

◼ Formed from heat and pressure changing an existing into a completely new rock.

◼ Parent Rock

◼ Igneous, Sedimentary, Metamorphic

◼ Texture:

◼ Foliated

◼ Unfoliated/Nonfoliated

Metamorphic Rocks

◼ Foliated- Parallel alignment of flattened mineral grains and pebbles

◼ Unfoliated-Rocks that are not banded and do not break into layers

Foliated

Gneiss

Parent - GraniteSlate

Parent –Shale/Mudstone

SchistParent – SlateGrandparent –Shale/Mudstone

Unfoliated

Marble

Parent: ChalkLimestone

Quartzite

Parent - Sandstone