Classify and Analyze the properties of soils

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1.1 Examine Modes Of Formation, Engineering Descriptions and Classification Of Common Rock Types.

Rocks.

Rock is the hard and durable material. Rock’s defined as the solid material forming the outer rocky shell or crust of the earth. Naturally- occurring mixtures of minerals, mineralogist, glass or organic matter.

There are three major groups of rocks by its origin

IGNEOUS

SEDIMENTARY

METAMORPHIC

IGNEOUS Rocks formed by the cooling and solidifying of molten materials.

Igneous rocks can form beneath the Earth's surface, or at its surface,

as lava.

Extrusive igneous rock is formed from lava (on earth’s surface)

and tends to solidify quickly.

Ex: Andesite Basalt, Obsidian, Pumice, Rhyolite and

Scoria

Intrusive igneous rock is formed from magma (inside the earth)

and tends to take a long time to solidify into rock.

Ex: Diorite, Gabbro, Granite and Pegmatite

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Above ground = from lava (extrusive igneous rock).

Usually have SMALL or NO crystals (they cooled too

quickly)

Igneous Rock Formation.

Extrusive igneous rock.

Igneous rocks are called fire rocks and are

formed either underground or above ground.

Underground, they are formed when magma deep

within the Earth becomes trapped in small pockets.

As these pockets of magma cool slowly they

become igneous rocks. Igneous rocks are also

formed when volcanoes erupt. Igneous rocks are

formed as the lava cools above ground. The upper

16 km of the Earth’s crust is composed of 95%

igneous rock.

Intrusive igneous rock.

Intrusive igneous rocks are formed

from magma that cools and solidifies underground.

These rocks are coarse grained. The mineral grains

in such rocks can generally be identified with the

unaided eye. They can be classified according to the shape and size of

the intrusive body and its relation to the other formations into which it

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3 intrudes. Intrusive formations are batholiths, stocks, laccoliths, sills, and

dikes.

SEDIMENTARY Sedimentary rock is a rock formed near Earth’s surface

from pieces of other rocks, plant or animal

remains, or by the build-up of chemical

solids.

All types of rock are continuously being

broken down into small fragments

called sediment.

This sediment can be compressed or

cemented together to form sedimentary

rock.

Sedimentary Rocks formed by the

deposition of material at the Earth's

surface and within bodies of water.

Sedimentation is the collective name for

processes that cause mineral and/or

organic particles (detritus) to settle and

accumulate or minerals to precipitate

from a solution.

There are three basic types

of sedimentary rocks.

1. clastic sedimentary rocks

Formed from mechanical weathering debris

Ex: Breccia, Conglomerate, Sandstone and Shale

2. chemical sedimentary rocks

Form when dissolved materials precipitate from

solution

Ex: salt and some limestone

3. organic sedimentary rock

Form from the accumulation of plant or animal

debris.

Ex: coal and some limestone

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4 Sedimentary Rock Formation.

As the sediments become buried under other sediment layers, pressures and temperatures increase. The sediment hardens into a sedimentary rock, or lithifies, after it has gone through the stages of compaction, dewatering, and cementation. During compaction, the grains of sediment are packed more tightly together. With increasing pressure some of the water between the sediment particles is squeezed out, dewatering the sediment. This process reduces the pore space, or open spaces between the grains. At this point, pressure and temperature conditions are such that certain minerals, usually calcite or quartz, fill some or all of the pore spaces and adhere to the sediment fragments, cementing them into a sedimentary rock.

Formed from sediments (rock fragments, mineral grains, animal & plant

remains) that are pressed or cemented together or when sediments precipitate

out of a solution.

• Compaction: is when pieces of sediment are squeezed together by the

weight of overlying layers (including water)

• Cementation of sediment occurs when minerals are deposited in a bed

of sediment and as the water evaporates the dissolved minerals form

crystals that “glue” the sediment particles to each other.

• These sediments are moved by wind, water, ice or

gravity.

• Sedimentary rocks represent 7% of the Earth’s crust, but

they cover 70% of the Earth’s surface.

• Sedimentary rocks are fossil-carrying rocks.

Classify and Analyze the properties of soils

5 METAMORPHIC

Metamorphic rock is a rock formed by the transformation of existing

rock, as a result of extreme heat and or pressure.

Rocks that have changed due to intense temperature and pressure

“Meta” means “change” and morphosis means “form” in Greek

Igneous, sedimentary and other metamorphic rocks can change to

become metamorphic rocks

There are two

basic types of metamorphic rocks.

1 Foliated metamorphic rocks.

Layered or banded appearance that

is produced by exposure to heat and

directed pressure.

Mineral grains are flattened and line

up in parallel bands.

Ex: Gneiss, phyletic, Schist and Slat

2 Non-foliated metamorphic rocks.

No bands are formed.

Ex: Marbles.

Formation Of Metamorphic Rocks . Schist rocks are metamorphic.

These rocks can be formed from basalt, an

igneous rock shale, a sedimentary rock or

slate, a metamorphic rock. Through

tremendous heat and pressure, these rocks were transformed into this

new kind of rock.

Gneiss rocks are metamorphic.

These rocks may have been granite, which is an igneous rock, but heat

and pressure changed it. You can see how the mineral grains in the rock

were flattened through tremendous heat and pressure and are arranged

in alternating patterns.

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1.2 Describe The Common Rock Forming Minerals and Their

Susceptibility to Weathering.

Minerals and rocks

Rock is natural, solid, nonliving material made of one or more minerals. Mineral is natural, nonliving material that makes up rock. Rocks get their properties from the minerals they contain. The properties of rocks include color and texture.

Grains are bits of minerals. They are big enough to see them. Texture is the size and pattern of a rock`s grains.

Properties to Minerals

Color Luster Streak Cleaving & Fracture Hardness Density Special Properties

Color Usually the first and most easily observed

-Some minerals are always the same color -Some minerals can have many colors

ROSE QUARTZ QUARTZ SMOKY QUARTZ

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7 The intrinsic color of the mineral.

NOTE: color is rarely diagnostic - usually a very poor Some examples...

Sulfur is normally yellow. Pyrite is normally brassy. Quartz can have almost any color

Luster General appearance of a mineral surface in reflected light Example: Dull or Shiny Types of Luster:

o Metallic/Glassy (Shiny) o Submetallic (Dull) o Nonmetallic (Dull)

METALLIC: opaque, looks like a metal such as gold,

METALLIC Opaque, looks like a metal such as gold,

silver, iron, etc. NON-METALLIC:

(needs to be more descriptive) – VITREOUS or GLASSY (Samples 3, 12) - strong glint (shiny like glass) – PEARLY (talc, some gypsum) - looks like mother-of-pearl – RESINOUS - reflects light in a manner similar to syrup or tree sap ("glazed") – EARTHY- dull, little or no reflection

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8 Streak

The color of a finely powdered mineral Determined by rubbing the mineral on a piece of unglazed porcelain (streak plate) More reliable than Color because weathering doesn’t change the Streak Color The streak (also called "powder color") of a mineral is the color of the powder produced when it is dragged across an un weathered surface.

Cleaving & Fracture Minerals break in certain ways depending on how the atoms are arranged

o Cleaving: When minerals break along flat surfaces Ex. Diamonds and Rubies

o Fracture: When minerals break unevenly or irregularly Ex. Quartz

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1) Talc

2) Gypsum

3) Calcite

4) Fluorite

5) Apatite

6) Feldspar

7) Quartz

8) Topaz

9) Corundum

10) Diamond

Hardness Hardness refers to a mineral’s resistance to being scratched Example: Diamond is the hardest mineral Mohr’s Hardness Scale: Scale 1 – 10 Reference Minerals – p. 66

Density Density is how much matter there is in a given amount of space Density of Water: 1 g/cm3 Specific Gravity = Object’s Density/Density of Water The specific gravity of an unknown mineral .

Special Properties Some minerals have unique properties: Taste (ex. Halite) Fluorescence (ex. Calcite & Fluorite) Chemical Reaction (ex. Calcite) Optical Properties (ex. Calcite) Radioactivity (ex. Radium & Uranium can be detected in a mineral) Magnetism (ex. Magnetite)

Softest

Hardest

1

2

3

4

5

6

7

8

10

9

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Common rock-forming minerals

Along with the common rock-forming minerals, we have included apatite, corundum, diamond, fluorite, topaz and talc to illustrate minerals used in Mosh Scale of Hardness.

1. Apatite

Apatite is a phosphate mineral . The name actually covers three different minerals (Fluor apatite, color apatite and hydroxyl apatite) depending on the predominance of either fluorine, chlorine or the hydroxyl group. These ions can freely substitute in the crystal lattice and all three are usually present in every specimen, although some specimens have close to 100% in one or other. The three are usually considered together due to the difficulty in distinguishing them in hand samples using ordinary methods.

Apatite is widely distributed in all rock types (igneous, sedimentary and metamorphic), but usually as small disseminated grains, or cryptocrystalline fragments. Large, well-formed crystals can be found in certain contact metamorphic rocks.

Chemical composition Ca5(PO4)3(OH, F, Cl) Hardness – 5 Specific gravity - 3.1-3.2 Transparency - Transparent to translucent Color - Typically green but also yellow, blue, reddish brown and purple Streak – White Luster - Vitreous to greasy Cleavage/fracture - Poor / conchoidal Crystal habit/mode of occurrence - Prismatic (hexagonal prism with hexagonal pyramid orpinacoid or both as termination), acicular /granular, massive

2. Augite

Augite is a member of the pyroxene group of simple silicates, in which the SiO4 tetrahedral are linked by sharing two of their four

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corners to form continuous chains. For this reason they are often referred to as single chain silicates.

Pyroxenes are subdivided into those with orthorhombic symmetry (orthopyroxenes), and those with monoclinic symmetry (clinopyroxenes), with augite being the most common of the clinopyroxenes.

Augite is commonly found in igneous rocks such as gabbros, basalts and andesite’s, and high grade metamorphic rocks (granulites).

Chemical composition - (Ca, Na)(Mg, Fe, Al)(Al, Si)2 O6 Hardness - 5-6 Specific gravity - 3.2-3.6 Transparency - Transparent to mostly translucent or opaque color - Dark green, brown and black Streak - Greenish white Luster - Vitreous Cleavage/fracture - Imperfect in two lengthwise directions at close to right angles / uneven Crystal habit/mode of occurrence - Prismatic (distinctive square cross section), tabular /granular

3. Biotitic

Biotite is a member of the mica group of silicates (sheet silicates), like chlorite and muscovite. It occurs in more geological environments than any of the other micas. It is a common rock forming mineral, being present in at least some percentage in many igneous rocks ( granite and rhyolite), and metamorphic rocks (schist, gneiss).

Chemical composition - K(Fe, Mg)3AlSi3O10

(F, OH)2 Hardness - 2.5-3 Specific gravity - 2.9-3.4 Transparency - Transparent to translucent color - Brown to black Streak - Very pale brown Luster - Vitreous to pearly Cleavage/fracture - Perfect in one direction producing thin sheets or flakes / uneven

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Crystal habit/mode of occurrence - Tabular (sheets or flakes) / granular

4. Calcite

Calcite is the only common non-silicate rock forming mineral, being instead calcium carbonate. It has two refractive indices causing a significant double refraction effect - when a clear calcite crystal is placed on an image, a double image is observed; See the sample below.

Calcite will fizz when dilute hydrochloric acid is placed on it. It may be fluorescent, phosphorescent; thermo luminescent and tri bioluminescent (see fluorite for definitions of these properties).

Calcite is one of the most ubiquitous minerals, being an important rock forming mineral in sedimentary environments. It is an essential component of limestone’s, and occurs in other sedimentary rocks. It also occurs in metamorphic and igneous rocks, and is common in hydrothermal environments. Calcite is a common vein filling mineral in many rock types.

Chemical composition - CaCO3 Hardness - 3 Specific gravity - 2.7 Transparency - Transparent to translucent color - Generally white or colorless, but also with light shades of yellow, orange, blue, pink, red, brown, green, black and grey Streak - White Luster - Vitreous to resinous Cleavage/fracture - Perfect in three directions at oblique angles / conchoidal Crystal habit/mode of occurrence - Prismatic (rhombohedra crystals)

5. Chlorite

Chlorite is a member of the mica group of minerals (sheet silicates), like biotite and muscovite.

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Chlorite is widespread in low grade metamorphic rocks such as slate and schist, in sedimentary rocks, and as a weathering product of any rocks that are low in silica (especially igneous rocks).

Chemical composition - (Fe, Mg, Al)6(Si, Al)4O10(OH)8 Hardness - 2-2.5 Specific gravity - 2.6-3.4 Transparency - Translucent to transparent color - Generally green (various shades) Streak - Pale green Luster - Vitreous, pearly Cleavage/fracture - Perfect / uneven Crystal habit/mode of occurrence - Tabular(rarely large individual barrel or tabular crystals with a hexagonal outline) / fine-grained, scaly or massive aggregates of small scales

6. Corundum

is the second hardest natural mineral known to science (1/4 the hardness of diamond). Gem varieties are sapphire and ruby.

Corundum may occur on a large scale in some pegmatites. It is also found in silica-poorhornfelses (a contact metamorphic rock).

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Chemical composition - Al2O3 Hardness - 9 Specific gravity - 4+ Transparency - Transparent to translucent color - Highly variable - white or color less, blue, red, yellow, green, brown, purple, pink Streak - White Luster - Vitreous to adamantine Cleavage/fracture - Non-existent / conchoidal Crystal habit/mode of occurrence - Prismatic (six-sided barrel shape that may taper into a pyramid, hexagonal prisms and blades) / massive, granular (called emery)

7. Diamond

is the hardest naturally occurring mineral, topping Mohs' Scale of Hardness with a relative hardness value of 10.

Diamond is a polymorph of the element carbon, and graphite is another. While the two share the same chemistry, C (elemental carbon), they have very different structures and properties. Diamond is hard, graphite is soft (the "lead" of a pencil). Diamond is an excellent electrical insulator, graphite is a good conductor of electricity. Diamond is the ultimate abrasive (its most important use), graphite is a very good lubricant. Diamond is transparent, graphite is opaque. Diamond crystallizes in the isometric system, graphite crystallizes in the hexagonal system. However, at surface temperatures and pressures graphite is the stable form of carbon. In fact, all diamonds at or near the surface of the Earth are currently undergoing a transformation into graphite, although this reaction is extremely slow.

Classify and Analyze the properties of soils

15 Facts about diamond:

Diamond is transparent over a larger range of wavelengths than any other substance, from the ultra-violet into the far infra-red.

Diamond conducts heat better than any substance - five times better than the next best element, silver.

Diamond has the highest melting point of any substance (3820 degrees Kelvin).

Diamond's atoms are packed closer together than the atoms of any other substance.

Diamond is only formed at high pressures. It is found in kimberlitic, an ultrabasic volcanic rock formed very deep in the Earth's crust. The extreme pressures needed to form diamonds are only reached at depths greater than 150km.

Chemical composition - C Hardness - 10 Specific gravity - 3.5 Transparency - Transparent to translucent in rough crystals color - Variable, tends toward pale yellows, browns, greys, and also white, blue, black, reddish, greenish and colorless Streak - White Luster - Adamantine to greasy Cleavage/fracture - Perfect in 4 directions forming octahedrons / conchoidal Crystal habit/mode of occurrence - Prismatic (isometric forms such as cubes and octahedrons)

8. Fluorite

is frequently fluorescent, it will glow under ultra-violet light. This occurs because certain electrons in the mineral absorb the energy from the ultra-violet light and jump to a higher energy state. The fluorescent light is emitted when those electrons jump down to a lower energy state and emit a light of their own.

Rare examples of fluorite may exhibit phosphorescence, i.e. they will continue to glow when removed from the ultra-violet light source. This occurs because electrons in the mineral have stored energy from the ultra-violet light which they then emit on a delayed basis.

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Rare examples of fluorite may exhibit thermo luminescence, they will glow when heated. This occurs because the mineral may contain chemical bonds that emit light when thermal energy (heat) is applied.

An even rarer property sometimes exhibited by fluorite is triboluminescence, where minerals glow when they are crushed, struck, scratched or even rubbed in some cases. The minerals contain chemical bonds that emit light when mechanical energy is applied to them.

Fluorite is a common vein mineral associated with mineral deposits.

Chemical composition - CaF2 Hardness - 4 Specific gravity - 3.2 Transparency - Transparent to translucent color - White if pure, but extremely variable - purple, blue, green, yellow, colorless, reddish orange, pink, white, brown; a single crystal can be multi-coloured Streak - White Luster - Vitreous Cleavage/fracture - Perfect in 4 directions forming octahedrons / hackly Crystal habit/mode of occurrence - Prismatic, always equant (typically cubes and to a lesser extent octahedrons as well as combinations of the two) / less common are crusts and botryoidalforms

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Garnet

is a more complex orthosilicate (than olivine, for example) in

which the SiO4tetrahedra are still independent. Garnet is commonly found in

highly metamorphosed rocks and in some igneous rocks. They form under the

same high temperatures and / or pressures that form those types of rocks.

Garnets can be used by geologists to gauge the temperature and pressure

under which a particular garnet-bearing rock formed.

Chemical composition - Fe3Al2Si3O12(almandine) Hardness - 6.5-7.5 Specific gravity - 3.6-4.3 Transparency - Transparent to opaque color - Variable - most commonly red, reddish brown Streak - White Luster - Vitreous to resinous Cleavage/fracture - Non-existent / conchoidal Crystal habit/mode of occurrence - Prismatic (12-sided rhombic, 24-sided trapezoidal) /granular, massive

9. Gypsum

has a very low thermal conductivity (hence its use as an insulating filler). A crystal of gypsum will feel noticeably warmer than, for instance, a crystal of quartz.

Gypsum is one of the more common minerals in sedimentary

environments. It is a major rock forming mineral that produces massive

beds, usually from precipitation out of highly saline waters.

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Chemical composition - CaSO4-2(H2O) Hardness - 2 Specific gravity - 2.3 Transparency - Transparent to translucent color - Usually white, colorless or grey, also shades of red, brown and yellow Streak - White Luster - Vitreous to pearly (especially on cleavage surfaces) Cleavage/fracture - Perfect in one direction, imperfect in two others / uneven (rarely seen)

Hornblende

is a member of the amphibole group of more complex silicates, in which the tetrahedral are linked to form a continuous chain twice the width of the pyroxene chains. For this reason they are often referred to as double chain silicates. Like the pyroxenes, they can be subdivided into those with orthorhombic symmetry and those with monoclinic symmetry . Hornblende is the most common of the clinoamphiboles.

Hornblende is commonly found in metamorphic rocks such as schist’s and gneisses, and igneous rocks such as diorites and decides.

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Chemical composition - Ca2(Mg, Fe, Al)5(Al, Si)8O22(OH)2 Hardness - 5-6 Specific gravity - 2.9-3.4 Transparency - Opaque color - Dark green to black Streak - Dark green Luster - Vitreous Cleavage/fracture - Imperfect in two directions at 56° and 124° / uneven Crystal habit/mode of occurrence - Prismatic,acicular, fibrous / massive, granular

10. Ilmenite

is the most important ore of titanium. It is similar in appearance to magnetite, but has a different crystal form and if it is magnetic then it's not as strongly so as magnetite. It will become magnetic when heated.

Ilmenite is a common accessory mineral in many igneous rocks and also found as a detrital mineral (in sands).

Chemical composition - FeTiO3 Hardness - 5-6 Specific gravity - 4.5-5 Transparency - Opaque color - Black Streak - Black Luster - Metallic Cleavage/fracture - Non-existent / conchoidal Crystal habit/mode of occurrence - Tabular (thin and thick tabular crystals with rhombohedra truncations, sometimes formed into rosettes) /massive and granular, as grains in some sands

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Magnetite

is a natural magnet, hence its name. This is a distinguishing characteristic of the mineral. Magnetite is a common accessory mineral in igneous rocks and is also found as a detrital mineral, particularly on the beaches west of Auckland (black sand).

.

Chemical composition - Fe3O4 Hardness - 5.5-6.5 Specific gravity - 5.2 Transparency - Opaque color - Black Streak - Black Luster - Metallic Cleavage/fracture - Non-existent / conchoidal Crystal habit/mode of occurrence - Prismatic (typically octahedral but rarely rhomb dodecahedral) / massive, granular

11. Muscovite

is a member of the mica group of silicate minerals (sheet silicates) in which the base of all of the SiO4 tetrahedral lie in one plane and three corners of the base are shared with the neighboring tetrahedral. This creates a strongly layered sheet-like structure, hence the term sheet silicate (the sheets are weakly bound together by layers of potassium ions). Muscovite, biotite and chlorite are all common mica group minerals.

Classify and Analyze the properties of soils

21 Muscovite is commonly found in metamorphic rocks such as schist’s and gneisses, sedimentary rocks (as the fine grained variety sericite), and in igneous rocks such as granite.

Although muscovite has perfect cleavage, individual sheets are quite durable and are often found in sands that have undergone erosion and transport that would have destroyed most other minerals. Sheets of muscovite have high heat and electrical insulating properties and are used in the manufacture of many electrical components. Muscovite sheets were used for kitchen oven windows before synthetic materials replaced them.

Chemical composition - KAl3Si3O10(OH)2 Hardness - 2-2.5 Specific gravity - 2.8 Transparency - Transparent to translucent color - White, silver, yellow, green and brown Streak - White Luster - Vitreous to pearly Cleavage/fracture - Perfect in one direction producing thin sheets or flakes / uneven Crystal habit/mode of occurrence - Tabular (sheets or flakes)

12. Olivine

is a simple orthosilicate in which the SiO4 tetrahedral are independent of each other. It is a solid solution of the end-members forsterite (Mg2SiO4) and fayalite (Fe2SiO4), although most examples are closer to the forsterite end-member.

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22 Olivine is very susceptible to alteration and often has a brownish weathering rind of assorted clay minerals.

Olivine is most commonly found in igneous rocks of low silica content, such as basalts and gabbros, and is occasionally found in metamorphic rocks.

Chemical composition - (Mg, Fe)2SiO4 Hardness - 6.5-7 Specific gravity - 3.2-4.4 Transparency - Transparent to translucent color - Yellowish green to green, also colorless, greenish brown to black Streak - White Luster - Vitreous Cleavage/fracture - Imperfect / conchoidal Crystal habit/mode of occurrence - Prismatic (equant to elongate) / granular, massive

13. Orthoclase

is a member of the feldspar group (like plagioclase) and is a framework silicate. Orthoclase, also known as alkali feldspar or K-feldspar, is one end-member of a solid solution between orthoclase and albeit. Orthoclase is found in silica-rich igneous rocks such as granite, and in high grade metamorphic rocks.

14. Plagioclase

is a member of the feldspar group (like orthoclase) and is a framework silicate. Plagioclase consists of a solid solution between the albite and anorthite end-members, and together with quartz is the most common of the rock forming minerals.

Chemical composition - KAlSi3O8 Hardness - 6 Specific gravity - 2.6 Transparency - Translucent to opaque (rarely transparent) color - Pinkish white, off-white, yellow, or shades of red, orange to brown Streak - White Luster - Vitreous Cleavage/fracture - Perfect in two directions, seldom twinned / hackly, conchoidal

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23 The twinning in plagioclase produces stacks of twin layers that are typically fractions to several mm thick. These twinned layers can be seen as striation like grooves on the surface of the crystal and, unlike true striations, these also appear on cleavage surfaces.

Plagioclase is found in almost all igneous rocks and most metamorphic rocks, but is less common in sedimentary rocks where it usually weathers to clay minerals or a fine grained variant of muscovite (sericite).

Chemical composition - CaAl2Si2O8 (anorthite), NaAlSi3O8 (albite) Hardness - 6-6.5 Specific gravity - 2.6-2.8 Transparency - Translucent to opaque (rarely transparent) color - Usually white, grey or colorless Streak - White Luster - Vitreous Cleavage/fracture - Perfect in two directions, commonly twinned / hackly, conchoidal Crystal habit/mode of occurrence - Prismatic, tabular

15. Pyrite

also known as "Fool's Gold" because of its brassy-yellow metallic colour, is the most common sulphide mineral in rocks of all ages, being found in virtually every geological environment. It is easily distinguishable from gold as it has a lower specific gravity. Pyrite is a common component of sedimentary rocks and metamorphosed sediments, is an accessory mineral in many igneous rocks, and forms large bodies in hydrothermal deposits.

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Chemical composition - FeS2 Hardness - 6-6.5 Specific gravity - 4.9-5.2 Transparency - Opaque color - Brassy yellow Streak - Greenish black Luster - Metallic Cleavage/fracture - Non-existent / hackly, conchoidal Crystal habit/mode of occurrence - Prismatic (cube, octahedron and pyritohedron [a dodecahedron with pentagonal faces]) / massive, granular

Quartz

is a complex silicate in which all the oxygen atoms of the SiO4 tetrahedral are shared between two tetrahedral, leading to complex 3-dimensional frameworks. For this reason, quartz is referred to as a framework silicate.

Quartz is among the most common of all rock forming minerals and is found in many metamorphic rocks, sedimentary rocks, and those igneous rocks that are high in silica content such as granites and rhyolites. It is a common vein mineral and is often associated with mineral deposits.

Cryptocrystalline varieties are used as semi-precious stones and for ornamental purposes. These varieties are divided more by character than by color. Chalcedony, or agate, is divided into innumerable types that have been named for locally common varieties. Some of the more beautiful types have retained their names while other names have faded into obscurity. Some of the more common are chrysoprase (a pure green agate), sard (a yellow to brown agate), sardonyx (banded sard), onyx (black and white agate), carnelian (a yellow to orange agate), flint (a colourful and microscopically fibrous form), jasper (a colourful impure agate) and bloodstone (a green with red speckled agate).

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Chemical composition - SiO2 Hardness - 7 Specific gravity - 2.65 Transparency - Transparent to translucent color - Clear is most common (pure quartz), also white or cloudy (milky quartz); but can be very variable - purple (amethyst), pink (rose quartz), grey or brown to black (smoky quartz) are also common; yellow to orange (citrine) are more rare; cryptocrystalline varieties can be multicolored Streak - White Luster - Vitreous Cleavage/fracture - Non-existent / conchoidal Crystal habit/mode of occurrence - Prismatic (hexagonal prism terminated with a six sided pyramid) / cryptocrystalline, massive

Talc

is the softest mineral, demonstrated by its position at the bottom of Mohs' Scale of Hardness with a relative hardness value of 1. It has a soapy, greasy feel.

Talc is formed by the hydrothermal alteration of ultrabasic rocks, or low grade thermal metamorphism of siliceous dolomites.

Most people know talc as the primary ingredient in talcum powder. However, talc is an important industrial mineral. Its resistance to heat, electricity and acids make it useful for lab counter tops and electrical switchboards. It is important filler in paints, rubber and insecticides.

Talc often replaces other minerals atom by atom to form pseudo morphs, taking the form of the replaced mineral. Thus, a specimen of what appears to be milky quartz would actually be talc, having a soapy feel and being able to be scratched with a fingernail.

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26 .

Chemical composition - Mg3Si4O10(OH)2 Hardness - 1 Specific gravity - 2.7-2.9 Transparency - Crystals translucent, masses opaque color - Green, grey and white to almost silver Streak - White Luster - Pearly, greasy Cleavage/fracture - Perfect in one direction / uneven Crystal habit/mode of occurrence - Tabular (thin flakes, never large crystals) / granular, cryptocrystalline

Topaz

is a common gem stone. Topaz crystals can reach very large sizes, with crystals in pegmatites occasionally measuring several meters long and weighing several hundred kilograms.

Topaz occurs mainly in felsic igneous rocks such as granite, granite pegmatite and rhyolite, and is often found in veins and cavities in such rocks.

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Chemical composition - Al 2{SiO4}(OH, F)2 Hardness - 8 Specific gravity - 3.5-3.6 Transparency - Transparent to translucent color - Colorless, pale yellow to amber; also pale shades of blue, green, orange, red Streak - White Luster - Vitreous Cleavage/fracture - Perfect in one direction /conchoidal Crystal habit/mode of occurrence - Prismatic (with a variety of terminal pyramids andpinacoids) / massive, granular

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1.3 Evaluate The Common Usage Of Rock and Un- Cemented Sediments For Construction.

Application of rocks to construction.

Rocks normally consist of several minerals, some essential, and

some accessory. A rock may be thought of as a "mineral environment." Each

rock type was formed under certain specific conditions, resulting in the

formation of a fairly predictable group of minerals. Rocks fall into three classes

according to their origin: Igneous - Sedimentary - Metamorphic

There are huge variations within each of these rock types,

caused by specific mineralogy and geology conditions, and while any

stone can be used for building, they each have constraints that make

them more or less suitable for different purposes.

Granite, sandstone and limestone can all be used for building walls,

but slate is only suitable for roofs and floors.

Some types of granite can contain mineral salts that cause

spalling, where the outer face of stone falls off slate can contain harmful

minerals that break down on exposure to the atmosphere causing stone

Classify and Analyze the properties of soils

28 damage. and sandstone can be too porous and fragile for load-bearing

structures.

LIMESTONE: A sedimentary rock, it is used mainly in the manufacture of

Portland cement.

SHALE: A sedimentary rock, well stratified in thin beds. It splits unevenly

more or less parallel to bedding plane and may contain fossils. It can be a

component of bricks and cement.

CONGLOMERATE: A sedimentary rock with a variable hardness, consisted of

rounded or angular rock or mineral fragments cemented by silica, lime, iron

oxide, etc. Usually found in mostly thick, crudely stratified layers. Used in the

construction industry.

SANDSTONE: A sedimentary rock more or less rounded. Generally thick-bedded, varicolored, rough feel due to uneven surface produced by breaking around the grains. Used principally for construction, it is easy to work, the red-brown sandstone of Triassic age, better known as "brownstone," has been used in many eastern cities.

GRANITE: An igneous-plutonic rock, medium to coarse-grained that is high in silica, potassium, sodium and quartz but low in calcium, iron and magnesium. It is widely used for architectural construction, ornamental stone and monuments.

PUMICE: An igneous-volcanic rock, it is a porous, brittle variety of rhyolite and is light enough to float. It is formed when magma of granite composition erupts at the earth’s surface or intrudes the crust at shallow depths. It is used as an abrasive material in hand soaps, emery boards, etc.

GABBRO: An igneous-plutonic rock, generally massive, but may exhibit a layered structure produced by successive layers of different mineral composition. It is widely used as crushed stone for concrete aggregate, road metal, railroad ballast, etc. Smaller quantities are cut and polished for dimension stone (called black granite).

BASALT: An igneous volcanic rock, dark gray to black, it is the volcanic equivalent of plutonic gabbro and is rich in ferromagnesian minerals. Basalt can be used in aggregate.

SCHIST: A metamorphic uneven-granular, medium to coarse grained, crystalline with prominent parallel mineral orientation. Goes from silvery white to all shades of gray with yellow to brown tones depending on the

Classify and Analyze the properties of soils

29 mineral concentration. Some schist’s have graphite and some are used as building stones.

GNEISS: A metamorphic uneven granular medium to coarse grained crystalline with more or less parallel mineral orientation. Colors are too variable to be of diagnostic value. Due to physical and chemical similarity between many gneisses and plutonic igneous rocks some are used as building stones and other structural purposes.

QUARTZITE: A metamorphic or sedimentary rock with crystalline texture, consists of rounded quartz grains cemented by crystalline quartz, generally white, light gray or yellow to brown. Same uses as sandstone.

MARBLE: A metamorphic even-granular grain to medium grained and may be uneven granular and coarse grained in calk-silicate rock. The normal color is white but accessory minerals act as coloring agents and may produce a variety of colors. Depending upon its purity, texture, color and marbled pattern it is quarried for use as dimension stone for statuary, architectural and ornamental purposes. Dolomite rich marble may be a source for magnesium and is used as an ingredient in the manufacture of refracting materials.

Google. 2015. Google. [ONLINE] Available

at:https://www.google.lk/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-

8#safe=active&q=common+usage+of+rocks+in+construction. .

Classify and Analyze the properties of soils

30

Snapshot of geologic, climatic,

Biological, and human history

2.1 Produce Soil Description For In – Situ and Sampled Materials.

Soil.

The upper layer of earth in which plants grow, a black or dark brown

material typically consisting of a mixture of organic remains, clay, and rock

particles.

Soil is the thin layer of loose mixture of small rock particles and rotting organic

matter that covers much of the world’s land surface.

Soil is made up of mineral grains. Water is held between the grains in the pore

spaces. 25% of the soil is air. Oxygen is essential Organic matter is both coarse and fine.

Soil Important.

Waste decomposer

Source material for construction,

medicine, art, etc.

Filter of water and wastes

Essential natural resource

Home to organisms (plants, animals and others)

Medium for plant growth

Producer and absorber of gases

Medium of crop production

Great integrator

Classify and Analyze the properties of soils

31 Purpose Of Soil Classification.

Classifying soils into Groups With similar behavior in terms of simple indices

can provide geotechnical engineers general guidance about engineering

properties of the soil through the accommodated experience.

(Priodeep Chowdhury;Lecturer;Dept. of CEE;Uttara University// Origin of USCS )

2.2 Classify Solis.

Soil Classification System

Particle Size Classification.

Textural classification.

Highway research Board classification. (HRB)

Unified soil Classification System.

Indian standard Classification System.

1. Describe the soil according to the British Soil Classification

System.

L.L = 45% PL = 18%

Plastic Index = LL – PL

= 45% - 18%

= 27%

Plastic Index = 27% Liquid Limit = 45%

Under the British Soil classification system we can identify this soil type.

This soil type is (ci ) - Clay Intermediate Soil.

Classify and Analyze the properties of soils

32

2. Calculate The Activity Of The Soil.

Activity Of The Soil = PI

% Of Clay Particle.

= 27

24.2

= 1.12

3. Determine the Liquidity Index When its Natural

Moisture Content is 29%

Liquidity Index = M - PL

PI

= 29 - 18

27

= 0.4074

2.3 Determine Basic Soil Properties.

Physical Properties Of Soil.

1. Color

The color of a soil can give clues to its

Health

Origin

Long term changes.

It can also indicate the color of the parent material.

2. Texture

Classify and Analyze the properties of soils

33 Texture refers to the relative proportion of sand , slit and clay in a

soil. It is one of the greatest factors in categorizing the types of soil.

3. Water Holding capacity

Soil’s capacity to hold water.

Micro pores - water is held in these small pore spaces in the form

of films adhering to the soil particles. This water is what the roots

can tap into and extract for plan use.

4. Permeability

Authorization of the soil to let substances pass through.

Macro pores - They do not hold water well because the water films

become too thick to adhere well to the surrounding soil particles.

This allows water and air to freely pass through.

WATER CONTENT OR MOISTURE CONTENT

The water content is defined as the ratio of mass of water to

the mass of soils.

Water content = (weight of water / weight of dry soil) 100%

BULK UNIT WEIGHT

Bulk unit weight is defined as the total weight of soil mass per

unit of total volume.

Bulk unit weight =

(total weight of soil mass / total volume of soil mass)100 %

DRY UNIT WEIGHT

Dry unit weight is defined as the weight of soil solids per unit

of total volume of the soil mass.

Classify and Analyze the properties of soils

34 Dry unit weight = (total weight of soil solids / total volume

of soil mass) 100%

SATURATED UNIT WEIGHT

When soil mass is saturated, its bulk unit weight is called the

saturated unit weight.

Saturated unit weight = ( total weight of saturated soil

mass / total volume of soil mass )

SUBMERGED UNIT WEIGHT

Submerged unit weight is defined as the ratio of submerged

weight of soil solids to the total volume of the soil mass.

Submerged unit weight = (submerged weight of soil solids

/ total volume of soil mass)

SPECIFIC GRAVITY

Specific gravity is defined as the ratio of the weight of a given

volume of soil solids to the weight of an equal volume of

distilled water.

Specific gravity = (weight of a given volume of soil solid /

weight of an equal volume of distilled water)

Classify and Analyze the properties of soils

35

VOID RATIO

It is defined as the ratio of the volume of voids to the volume

of solids.

Void ratio = (volume of voids / volume of solids)

POROSITY(n)

It is defined as the ratio of volume of voids to the total volume.

Porosity = (volume of voids/ total volume)

DEGREE OF SATURATION

It is defined as the ratio of the volume of water to the volume of voids.

Degree of saturation = ( volume of water / volume of voids)

In case of fully saturated soil, voids are completely filled with water.

There is no air.

S r = 1

In case of fully dry soil, voids are completely filled with air.

There is no water

AIR CONTENT

It is defined as the ratio of the volume of air to the volume of voids.

Air content = (volume of air/ volume of voids)

PERCENTAGE AIR VOIDS

It is defined as the ratio of the volume of air to the total

volume.

Percentage air voids = (volume of air/ total volume )

It is represented as a percentage

Classify and Analyze the properties of soils

36 BULK DENSITY (b)

The bulk density is defined as the total mass per unit volume.

b = = (m/v)

It is expressed as kg/m³.

1cm³ = 1ml

DRY DENSITY

The dry density is defined as the mass of solids per unit total

volume.

d =(md /v) = (ms /v)….. Kg/m³

SATURATED DENSITY

The saturated density is the bulk density of soil when it is fully

saturated.

sat = (Msat / V) ….. Kg/m³

Classify and Analyze the properties of soils

37

3.1 Explain The Measurement of Geotechnical Design Parameters.

1. Shear strength 2. Compressive strength

Shear strength Of Soil.

The shear strength is most important property of soil. It is resistance

provided by soil to sliding along any plane inside it. The nature of shear

strength is most difficult to grasp. Shear strength depends on interaction

between particles and shear failure occur when particles slides over each

other due to excessive shearing stresses. It is very much important to

understand behavior and analyze the property of shear strength to

provide soil stability regarding shear failures such as bearing capacity,

slope stability and lateral pressures on earth retaining structures.

Shearing resistance of soil is constituted basically of the structural

resistance, the frictional resistance and cohesion. The shear resistance in

cohesion less soil is of friction alone and in other soils is result of both

friction and cohesion. The shear strength of soil is determined in

laboratory as well as in field.

τf = c + σ’ tan φ τf = shear strength c = cohesion φ = angle of internal friction Consider the following situation:

A normal stress is applied vertically and held constant A shear stress is then applied until failure

Classify and Analyze the properties of soils

38 or any given normal stress, there will be one value of shear

stress If the normal stress is increased, the shear stress will typically

increase in sands and stay the same in clays

Cohesion

between particles (stress independent component) •Cementation between sand grains •Electrostatic attraction between clay particles

Angle Of Friction

Soil friction angle is a shear strength parameter of soils. Its definition is derived from the Mohr-Coulomb failure criterion and it is used to describe the friction shear resistance of soils together with the normal effective stress.

In the stress plane of Shear stress-effective normal stress, the soil friction angle is the angle of inclination with respect to the horizontal axis of the Mohr-Coulomb shear resistance line.

Classify and Analyze the properties of soils

39 3.2 Discuss the Methods Of Ground Investigation And in situ sample acquisition and Testing.

The various type of site Exploration.

1. Open excavation.

2. Borings

3. Sub surface sounding

4. Geo physical method

These are site exploration methods. I explain 2 methods in my assignment.

1. Trial pit.

2. Borehole.

TRIAL PIT AND BOREHOLE

• Excavation of ground in order to study or sample the composition

and structure of the subsurface, usually dug during a site

investigation, a soil survey or a geological survey.

• To identify whether the site is suitable for the proposed work.

Trial pit

This method involving the open

excavation. Very cheapest

method in site exploration.

Because can we using any type of

soil in this method.

• Shallow excavations to a depth no greater 6m.

• Support use are timbering, steel frames with hydraulic jack, battered or

tapered side.

• Suitable for most low rise developments.

• Suitable for the investigation of all types of land.

Classify and Analyze the properties of soils

40

Trial pitting can be carried out by a variety of methods from hand dug pits to machine excavated trenches. Trial pitting is generally carried out to a maximum depth of 4.5m with standard excavation plant and, depending on soil conditions, is generally suitable for most low rise developments.

All trial pit investigations are supervised by experienced engineers with a thorough understanding of geology and soil mechanics.

Additional testing in trial pits can include soak away testing, CBR testing and in-situ strength testing.

Borehole

Boreholes are a common method of site investigation. Using a

vehicle-towed rig most sites can be investigated. In-situ testing techniques

including Standard Penetration Testing, Permeability Testing, Borehole Vane

Testing and Packer Testing can all be carried out in the boreholes in order to

provide information for geotechnical design. Continuous disturbed and

undisturbed samples are retrieved from the boreholes for inspection and

logging by engineers and subsequent testing in our laboratories.

The various method commonly used.

Auger boring.

Auger and shell boring.

Wash boring

Precaution boring

Rotary boring

Auger boring. Augers are used in cohesive and other soft soils above water

table.

Operating manually or mechanically.

Hand augers used depth up to 6m

Mechanically can also be used in gravelly soil.

Classify and Analyze the properties of soils

41 Augers are 2 types.

1. Spiral auger

2. Post hole auger

Augers and shell boring Can be used for making deep boring.

Hand operated rigs are used for depth up

to 25m

Mechanized up to 50m

Suitable for soft to stiff clay.

Shell for very stiff and hard clay.

Wash boring

Simple method for advancing holes in all

type of soil.

Boulders and rock cannot be penetrated by

this method.

Percussion boring. In this method soil and rock formations are

broken by repeated bellows of heavy chisel

or bit suspended by a cable or drill rod.

Water is added to the hole during boring.

The method suitable for advancing in all

type of soils.

Rotary boring. Very fast method of advancing hole in both

rocks and soils.

Drill bit fixed to the lower end of the drill

rods.

Always kept in firm contact with the

bottom of the hole.

Classify and Analyze the properties of soils

42 3.3 Carry out Laboratory Measurements on soil.

Density in Placed By Sand Cone Test.

Description of Test This test method describes the procedure for determining the density of soil cement base course in place. APPARATUS AND MATERIALS Equipment Required

Sampling tools - hammer, chisel, trowel, large spoon, banister brush. Containers - two 2.3 L size mason jars for which the tare weights are

known. Balance - 0.1 g accuracy Sand Cone Density Apparatus - consisting of a double cone assembly

having a cylindrical valve between the cones with an orifice 12.7 mm in diameter.

The upper cone will be large enough to serve as a hopper to hold the density sand. Density Sand - prepare a supply of air dried clean flowing sand which

passes the 2.00 mm sieve and is retained on the 900 mm sieve. Thoroughly mix and pre

weigh 5000 g samples and store in a clean dry place. Sieves - a 18.00 mm, 200 mm, 900 mm and a 400 mm Canadian Metric

Standard Sieve. Calibration Mold - a cylindrical mold 127 mm in diameter with 28.6 mm

wide flange around the upper rim. The volume of the mold will be stamped into the

metal. Drying Equipment - oven - capable of maintaining a temperature of

110oC and a hot plate or stove. Thermometers - ranging between 35oC to 150oC.

Classify and Analyze the properties of soils

43 Determination of Unit Weight by Sand

Place the calibration mold in a pan. Set the sand cone device in place on the flange of the calibration mold

and close the valve. Place the pre weighed 5000 g sample of density sand in the hopper. Open the valve and keep it open until the sand has stopped flowing and

then close. Reweigh the sand remaining in the hopper. The difference between the original (5000 g) and final weight will be the

"weight of sand to fill calibration mold and cone." The weight of sand to fill the lower cone will be determined in a similar

manner. Place the sand cone device on a flat surface and allow the sand (5000 g)

to run into the cone. The difference between the original and final weight of

sand in the hopper shall be recorded as the "weight of sand to fill cone." Calculate the unit weight of sand from the above determinations. If a base plate is to be used in the taking of density tests, the plate shall

be placed between the flat surface and the cone. Test as above to determine the

weight of sand to fill the cone and base plate.

Density-In-Place by Sand Cone

Select the site to be tested at random or where sample for proctor has been taken.

Scrape smooth and remove all loose material at the location to be tested. Start a small hole in the center with a hammer and chisel. Carefully enlarge the hole outwards and downwards with small hand

tools until sufficient material has been removed to fill the two 2.3 L mason jars.

Exercise extreme care in removing the material so as not to cause a disturbance to

surrounding material. Do not project the hole below the level of the material tobe tested.

Place all the material removed from the hole in the mason jars except stone

Classify and Analyze the properties of soils

44 particles larger than 18 mm. These stones will be replaced in the hole

during the volume measurement with density sand. The sealed jars will be taken to

the lab and weighed to the nearest gram and the tare weight subtracted. The

result will be recorded as "weight of material removed." Carefully place and centre the sand cone device over the test hole with

the valve closed. Place the 5000 g of density sand into the storage hopper of the sand

cone device. Turn on the valve. If stone particles are to be replaced in the hole, allow a small quantity of

sand to run into the hole, close the valve, lift the apparatus, and partially imbed

these particles into the sand. Replace the device, turn on the valve, allow the

sand to run until the test hole and funnel are completely filled, and turn off the

valve. Remove the apparatus and remove the sand from the test hole and place

in a large cloth bag along with other used sand for later reclaiming. Weigh the unused sand in the hopper to determine the amount of sand

used in the test. This weight of sand will be used to obtain the volume of hole and

funnel. Remove the soil cement mixture from the two mason jars and mix

thoroughly together and obtain a representative sample for moisture

determination. Place sample in a suitable tared pan and weigh. Dry sample carefully to a constant weight. Weigh sample and pan after cooling. The difference between the wet and dry weights will be recorded as

"weight of moisture" and dry weight less weight of pan will be recorded as "weight

of dry sample.

Classify and Analyze the properties of soils

45

Minerals, Rocks & Rock Forming Processes. 2015. Minerals, Rocks & Rock Forming Processes. [ONLINE] Available at:http://www.indiana.edu/~geol105/1425chap5.htm.

Basalt: Igneous Rock - Pictures, Definition, Uses & More. 2015. Basalt: Igneous Rock - Pictures, Definition, Uses & More. [ONLINE] Available

at:http://www.geology.com/rocks/basalt.shtml.

Slide Shere Presentations.

Google. 2015. Google. [ONLINE] Available

at:https://www.google.lk/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-

8#safe=active&q=common+usage+of+rocks+in+construction. .

2015. . [ONLINE] Available

at:http://www.engr.uconn.edu/~lanbo/CE240LectW032Soilclassification.pdf.

BCAS Engineering Geology Lecture Tute.