Transcript UNIVERSAL COLLEGE OF

ENGINEERING &
TECHNOLOGY
BY
BHORANIYA AHEMADABBAS A. (130460106008)
MINERALOGY :
Mineralogy is that branch of geology which
deals with various aspects related to minerals like mode
of formation, composition, occurance, association,
properties, uses, etc.
In nature more than 2000 minerals are
known to occur. The minerals may be divided in to two
broad groups:
(i) Rock forming minerals
(ii) Ore forming minerals
Rock forming minerals are those which are
found in abundance in the rocks of the earth’s crust. Ore
forming minerals are those which are of economic value
and which do not occur in abundance in rocks.
Table No. 1
Sr. No.
Mineral
Group
Exampels
1
Oxides
Quartz, Magnetite, Hematite Limonite
etc.
2
Silicates
Felspar, Mica, Horublende, Augite,
Olivines, etc.
3
Carbonates Calcite, Dolomite, Siderite, etc.
4
Sulphides
Pyrites, Galena, Sphalerite, etc.
5
Sulphates
Gypsum, etc.
6
Chlorites
Rocksalt, etc.
-> Common rock forming minerals :
Rock forming minerals are very abundant
in the earth’s crust. More than 1600 minerals species are
known at present. Bust most of these are very rare and
hence of academic interest only. According to an estimate
99.9% of the earth’s crust is composed of 20 – 25 rock
forming minerals only. Economic minerals are therefore
very scarce.
Table no. 2 shows the approximate chemical
composition of the earth’s crust.
Table no. 3 shows the minerals composition
of rocks.
Sr.
No.
Element
Percentage
1
Oxygen
46.71
2
Silicon
27.69
3
Aluminium
8.07
4
Iron
5.05
5
Calcium
3.65
6
Sodium
2.75
7
Potassium
2.58
8
Magnesium
2.08
9
Titanium
0.62
10
Hydrogen
0.14
11
Phosphorus
0.13
12
Carbon
0.0094
13
Rest
0.5206
100%
SR.
No.
Mineral
1
Felspar
59.5
2
Pyroxenes & amphiboles
16.8
3
Quartz
12.0
4
Biotite
3.8
5
Titanium
1.5
6
Apatite
0.6
7
Accessory mineral
5.8
→ FELDSPARS
Feldspars (KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8) are a group of rock-forming tectosilicate
minerals that make up as much as 60% of the Earth's crust.
Feldspars crystallize from magma as veins in both intrusive and extrusive igneous rocks
and are also present in many types of metamorphic rock. Rock formed almost entirely of
calcic plagioclase feldspar (see in fig.) is
→ PYROXENES
The pyroxenes are a group of important rock-forming inosilicate minerals found in
many igneous and metamorphic rocks. They share a common structure consisting of
single chains of silica tetrahedra and they crystallize in the monoclinic and
orthorhombic systems. Pyroxenes have the general formula XY(Si,Al)2O6 (where X
represents calcium, sodium, iron+2 and magnesium and more rarely zinc, manganese
and lithium and Y represents ions of smaller size, such as chromium, aluminium, iron+3,
magnesium, manganese, scandium, titanium, vanadium and even iron+2). Although
aluminium substitutes extensively for silicon in silicates such as feldspars and
amphiboles, the substitution occurs only to a limited extent in most pyroxenes.
→ AMPHIBOLE
Amphibole is the name of an important group of generally dark-colored, inosilicate
minerals, forming prism or needle like crystals, composed of double chain SiO4
tetrahedra, linked at the vertices and generally containing ions of iron and/or
magnesium in their structures. Amphiboles can be green, black, colorless, white,
yellow, blue, or brown
DIFFERENCE BETWEEN PYROXENES AND AMPHIBOLES
Amphiboles crystallize into two crystal systems, monoclinic
and orthorhombic. In chemical composition and general
characteristics they are similar to the pyroxenes. The chief
differences from pyroxenes are that (i) amphiboles contain
essential hydroxyl (OH) or halogen (F, Cl) and (ii) the basic
structure is a double chain of tetrahedra (as opposed to the
single chain structure of pyroxene). Most apparent, in hand
specimens, is that amphiboles form oblique cleavage planes (at
around 120 degrees), whereas pyroxenes have cleavage angles
of approximately 90 degrees. Amphiboles are also specifically
less dense than the corresponding pyroxenes. In optical
characteristics, many amphiboles are distinguished by their
stronger pleochroism and by the smaller angle of extinction (Z
angle c) on the plane of symmetry. Amphiboles are the primary
constituent of amphibolites
Quartzite (from German Quarzit) is a hard, non-foliated metamorphic rock which was
originally pure quartz sandstone. Sandstone is converted into quartzite through heating
and pressure usually related to tectonic compression within orogenic belts. Pure
quartzite is usually white to grey, though quartzites often occur in various shades of pink
and red due to varying amounts of iron oxide (Fe2O3). Other colors, such as yellow,
green, blue and orange, are due to other mineral impurities
→USES
Because of its hardness and angular shape,
crushed quartzite is often used as railway
ballast.Quartzite is a decorative stone and
may be used to cover walls, as roofing tiles, as
flooring, and stairsteps. Its use for
countertops in kitchens is expanding rapidly.
It is harder and more resistant to stains than
granite. Crushed quartzite is sometimes used
in road construction. High purity quartzite is
used to produce ferrosilicon, industrial silica
sand, silicon and silicon carbide. During the
Stone Age quartzite was used, in addition to
flint, quartz, and other lithic raw materials,
for making stone tools.
Biotite is a common phyllosilicate mineral within the mica group, with the approximate
chemical formula K(Mg,Fe)
3AlSi
3O
10(F,OH)
2. More generally, it refers to the dark mica series, primarily a solid-solution series between
the iron-endmember annite, and the magnesium-endmember phlogopite; more aluminous
endmembers include siderophyllite. Biotite was named by J.F.L. Hausmann in 1847 in
honour of the French physicist Jean-Baptiste Biot, who, in 1816, researched the optical
properties of mica, discovering many unique properties.
Biotite is a sheet silicate. Iron, magnesium, aluminium, silicon, oxygen, and hydrogen form
sheets that are weakly bound together by potassium ions. It is sometimes called "iron mica"
because it is more iron-rich than phlogopite. It is also sometimes called "black mica" as
opposed to "white mica" (muscovite) – both form in some rocks, in some instances side-byside
→ TITANIUM :
A metallic element, titanium is recognized for its high strength-toweight ratio. It is a strong metal with low density that is quite ductile (especially
in an oxygen-free environment), lustrous, and metallic-white in color. The
relatively high melting point (more than 1,650 °C or 3,000 °F) makes it useful as a
refractory metal. It is paramagnetic and has fairly low electrical and thermal
conductivity
Apatite is a group of phosphate minerals, usually referring to hydroxylapatite,
fluorapatite and chlorapatite, named for high concentrations of OH−, F− and Cl− ions,
respectively, in the crystal. The formula of the admixture of the four most common
endmembers is written as Ca10(PO4)6(OH,F,Cl)2, and the crystal unit cell formulae of the
individual minerals are written as Ca10(PO4)6(OH)2, Ca10(PO4)6(F)2 and Ca10(PO4)6(Cl)2.
Apatite is one of a few minerals produced and used by biological microenvironmental systems. Apatite is the defining mineral for 5 on the Mohs scale.
Hydroxyapatite, also known as hydroxylapatite, is the major component of tooth enamel
and bone mineral. A relatively rare form of apatite in which most of the OH groups are
absent and containing many carbonate and acid phosphate substitutions is a large
component of bone material
∙ CIVIL ENGINEERING IMPORTANCE OF
ROCK – FORMING MINERALS :
Undoubtedly, among different minerals,
economic minerals by virtue of their utility and inherent
value, are very important and evoke interest. However,
from civil engineering point of view, they are not relevant
and, on the contrary, knowledge of rock forming minerals
is very much necessary because:
(1) The civil engineering need to know the properties of
rocks precisely to enable them to consider different rocks
for various purposes such as foundation rocks, road
metals, concrete aggregates, building stones, flooring
material, roofing material, etc. All properties of rocks are
in turn, dependent on the properties of their constituent
minerals. Thus properties of civil engineering importance
such as strength, durability, hardness, appearance, etc. Of
rocks can be assessed only with the knowledge of the
minerals that forms rocks.
(2) The economic minerals, since they are scrace, do not
influence the properties of rocks and are hence irrelevant
from the civil engineering point of view. But, if they
happen to occur in large quantities, their economic value
will not permit them to be used either as construction
materials or as foundation sites.