Minerals-Rocks-Weathering-Erosion-Deposition

Minerals-Rocks-Weathering-Erosion-= Deposition

Minerals http://www.galleries.com/minerals/byname.htm

We have all seen rubies, e= meralds, sapphires, and diamonds, to name a few types of minerals. Minerals are the building blocks of rocks and rocks are the building blocks of solid Earth. Almost all minerals are compoun= ds consisting of two or more elements that are chemically combined whereas, an elements is a substance composed of a single kind of atom.

1. Minerals occur naturally. 2. They are inorganic (nonliving) solids. 3. Minerals have a chemical compos= ition usually of two or mode elements chemically combined to form a compound that= can be written with a chemical formula. 4. Minerals have a crystal structure.

5. A mineral is always a solid.<= /o:p>

Mineral Characteristics

Quartz<= o:p>

Coal

naturally occurring=

yes

yes

inorganic

yes

no

solid<= /p>

yes

yes

chemical composition

yes

no

crystal structure

yes

no

Minerals form from magma.<= span style=3D'mso-spacerun:yes'> Crystals form when magma cools. Minera= l size is determined by where the magma cools and how the magma cools. Large crystals (amethyst crystals = in a geode) form from slowly cooling magma beneath Earth’s crust. Small crystals form from fast cool= ing magma beneath Earth’s crust. Compounds dissolving in water also may form crystals as the water evaporates. Larger crystals f= orm from slow evaporation. An exa= mple is rock salt.

The atoms of minerals are = arranged in definite repeating patterns forming crystals with flat sides meeting at sharp edges and corners. Mine= rals can be identified by the physical properties of color, luster, hardness, streak, density, crystal shape, cleavage and fracture. A geode is a rounded holl= ow rock that often is lined with mineral crystals. This happens when dissolved minera= ls in water get into the cracks or hollows of rocks and slowly crystallization occurs.

1. Minerals form by crystallization of magma and lava.

2. Minerals form crystallization of materials dissolved in water.

For more information on mi= nerals, use the following website.

http://www.galleries.= com/minerals/byname.htm

Minerals are the source of gemstones as in jewelry, metals, and many materials used in many products.<= span style=3D'mso-spacerun:yes'> To get metal from a mineral, rocks containing the mineral are located, mined, and processed to take out the me= tal for further use

Rocks

Rocks are the building blo= cks of the Earth. It is easy to reco= gnize a rock. In science, a rock is a hard substance made of on= e or more minerals. Rocks can = also be made of volcanic glass or opals which are not crystalline. Geologists classify rocks into thr= ee groups according to how they are formed.&n= bsp; The three groups of rocks are igneous, sedimentary, and metamorphic. Geologists observe m= ineral composition, color and texture of rocks when studying the Earth’s cru= st.

Sedimentary Rock forms as particles are carried and deposited by the wind or water. The particles include mud, sand, pebbles, shells, bones, leaves, stems or any type of dead stuff. Time presses all the materials and= they become cemented together and form rocks called sedimentary rocks. Erosion, deposition, compaction, a= nd cementation form sedimentary rock. The three groups of sedimentary rock are clastic (shale, sandstone, conglomerate), organic (coal and limestone), and chemical (minerals dissolv= ed in a solution) rock.

Metamorphic Rock form when there is great heat, great pressure, and chemical reactions. When existing rocks are subjected = to all three conditions, new rocks called metamorphic rocks form. The new rocks have new physical and chemical properties making them different than the original rocks. Metamorphic rocks with grains in parallel layers or bands are called foliated or banded. Examples are s= late, schist, and gneiss which are formed from granite.&= nbsp; Metamorphic rocks with the grains arranged randomly are called nonfoliated or nonbanded. Marble and quartzite are examp= les of nonfoliated metamorphic rock. Quartzite forms from sandstone.&nbs= p; Metamorphic rock is used in building and sculpture.

Igneous Rock i= s formed from molten rock. Rocks that = form from lava are called extrusive roc= ks or volcanic rocks such as basalt or obsidian and pumice which floats becaus= e of gas bubbles that formed as the rock hardened. Rocks that form deep in the Earth = are called
intrusive rocks or plutonic rock that forms from magma pushing upward towards other rocks where it then hard= ens such as granite. Science classifies igneous rocks by composition (minerals), and texture (shape, size, arrangement, and mineral distribution).

Example of a Mineral Composition of Granite:

Feldspar 63% (light minera= l)

Quartz 27% (light mineral)=

Mica, hornblende 10% (dark minerals)

The Rock Cycle

The Rock Cycle is the constant and continuous changing of rocks from one kind of rock into another kind of rock over very long periods of time as part of Earth’s Histor= y. Igneous, sedimentary, and metamorp= hic rocks change continuously through the rock cycle because of erosion, deposi= tion, heat and pressure, melting, cooling, and volcanic activity. Plate movement activity starts the= rock cycle by the formation of magma which is the source of igneous rock. As the plates move, faulting, fold= ing, and movements in the crust form sedimentary and metamorphic rocks.

Weathering

Rocks crack, break, and cr= umble constantly as a natural process on Earth’s surface. Weathering

is the slow natural proces= s of breaking down rocks and other materials on the surface of Earth.=

Mechanical Weathering is the breaking down of rock that does not change the chemical composition of = the rocks. This process can be ca= used by temperature changes which c= ause the surface to exfoliate, crack or break off. Another type of mechanical weather= ing is freezing and melting of water = on rocks and in the cracks of rocks which breaks the rocks down. Plants and animals (organic activity) also cause mechanical weathering. Gravity pulls and rock downward where the rocks crash and collide breaking into sma= ller pieces. Abrasion is mechanical weathering as wind, water or other forces carry solid particles that come in contact with rock and wear away the surf= ace of rocks. <= /p>

Chemical Weathering is the breaking down of rock that changes the chemical composition of the rocks. Chemical reactions add= or remove minerals from rocks. Chemical reactions can break down and decompose the minerals in rocks. Water, carbon dioxide,= oxidation, and acids reacting with rocks are forms of chemical weathering that change = the chemical composition of the rocks.

Soil Formation

Soil is the result of the weathering of rocks. Weathering over time breaks the ro= cks into smaller and smaller pieces that form soil. Living organisms help to form soil= and make it fertile. Living organ= isms die and decompose adding rich organic substances to the soil. This decaying material is called humus. Weathered rocks (80%) = and humus are the two main ingredients of soil. Water and air are also present = in soil.

Erosion and Deposition

Erosion is the= moving of weathered products from one place to another caused by waves, glaciers, wind, gravity or moving water. Gravity moving sediments downward is called mass wasting. Deposition is the process that lays sediments down in a new location. <= /span>

http://www.dartmoor-npa= .gov.uk/lab-erosion

http://www.dartmoor= -npa.gov.uk/lab-erosion.pdf

=

Mineral Characteristics	Quartz<= o:p>	Coal
naturally occurring=	yes	yes
inorganic	yes	no
solid<= /p>	yes	yes
chemical composition	yes	no
crystal structure	yes	no