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Mansoura University
Faculty of Science
Marble Industry in Egypt
Prepared By:
Mahmoud Fakhry Abd El-Kader
Mahmoud Abd El-Kader Mosaad
Mahmoud Mohamed El-Shobaki
Mohanad Mohamed El-Abyad
Ahmed Ahmed Shuaaib
3rd at Petroleum & Mining geology program
Under the supervision of
Dr. Ahmed M.S. Abd El-Gawad
Oct. 2016
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Content
Content
Page
Introduction....................................................................
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Part 1
Marble
1/1
Occurrence…………………………………………………………………………………….
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2/1
Mineral Composition …………………………………………………………………….
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3/1
Physical Properties ……………………………………………………………………….
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4/1
Locality …………………………………………………………………………………………
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5/1
Types…………………………………………………………………………………………….
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6/1
Uses………………………………………………………………………………………………
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7/1
Mining…………………………………………………………………………………………..
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8/1
Economic Value …………………………………………………………………………….
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Part 2
Granite
1/2
Occurrence…………………………………………………………………………………....
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2/2
Mineral Composition ……………………………………………………………………..
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3/2
Physical Properties ………………………………………………………………………..
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4/2
Locality ………………………………………………………………………………………….
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5/2
Types………………………………………………………………………………………………
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6/2
Uses……………………………………………………………………………………………….
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7/2
Mining……………………………………………………………………………………………
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8/2
Economic Value ……………………………………………………………………………..
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References ……………………………………………………………………..
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Introduction
Marble is a highly valued rock known for its strength, aesthetics, ability to be
polished and resistance to most weathering. It has a variety of uses and has been
used by current or ancient civilizations for building applications and statues. This
material comes in a variety of textures depending on the composition and how it
is formed. Highly valued as a construction, flooring and sculpture material since
ancient times, most famously by the Ancient Greeks and Romans, marble is prized
for its smooth, soft nature, its strength and purity; it can be found in many
countries and is usually associated with refinement and culture, often polished to
give a flawless finish. The name marble comes from the Greek word ‘Marmaros‘
which means ‘shining stone’.
Granite is a very common type of rock that has been, and is still used for a variety
of purposes. Its strength makes it an excellent building material used in the past
and in the present, and it isn’t very porous or affected by temperature. Granite is
even incredibly resistant to weathering and chemical erosion (even acid rain). The
color of granite can range from pink to gray and it keeps great consistency in its
texture and coloring.
With so many useful properties, it’s no wonder that granite continues to be used
for monuments, building stones, gravestones, flooring, kitchen counter-tops, and
a variety of other applications. Granite is so strong and durable that the word
itself has a second meaning that can be used as an adjective to describe
something with similar physical properties. It’s definitely more than enough to
make you wonder what exactly this incredible rock is made of. Interestingly
enough, the chemical composition of granite can vary quite a bit, depending on
where it is formed and the magma it was formed from.
Being an igneous rock, granite is formed from the solidification and cooling of
magma. It is also an intrusive rock which means that it does not form on the
surface but actually underneath the surface. What elements are present in the
magma will directly affect what minerals are formed when it cools. Crystallization
will occur when the granite starts cooling, and many different minerals will form
at varying rates. Over a very long period of time, the granite will cool and get
pushed to the surface.
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Marble
A non-foliated metamorphic rock that forms when limestone is subjected to heat
and pressure.
Another Definition of Marble:
The name "marble" is used in a different way in the dimension stone trade. Any
crystalline carbonate rock that has an ability to accept a polish is called "marble."
The name is sometimes used for other soft rocks such as travertine, verd antique,
serpentine, and some limestones.
1/ Occurrence:
What is Marble?
Marble is a metamorphic rock that forms when limestone is subjected to the heat
and pressure of metamorphism. It is composed primarily of the mineral calcite
(CaCO3) and usually contains other minerals, such as clay minerals, micas, quartz,
pyrite, iron oxides, and graphite. Under the conditions of metamorphism, the
calcite in the limestone recrystallizes to form a rock that is a mass of interlocking
calcite crystals. A related rock, dolomitic marble, is produced when dolostone is
subjected to heat and pressure.
How Does Marble Form?
Most marble forms at convergent plate boundaries where large areas of Earth's
crust are exposed to regional metamorphism. Some marble also forms by contact
metamorphism when a hot magma body heats adjacent limestone or Dolostone.
Before metamorphism, the calcite in the limestone is often in the form of lithified
fossil material and biological debris. During metamorphism, this calcite
recrystallizes and the texture of the rock changes. In the early stages of the
limestone-to-marble transformation, the calcite crystals in the rock are very small.
In a freshly-broken hand specimen, they might only be recognized as a sugary
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sparkle of light reflecting from their tiny cleavage faces when the rock is played in
the light.
As metamorphism progresses, the crystals grow larger and become easily
recognizable as interlocking crystals of calcite. Recrystallization obscures the
original fossils and sedimentary structures of the limestone. It also occurs without
forming foliation, which normally is found in rocks that are altered by the directed
pressure of a convergent plate boundary.
Recrystallization is what marks the separation between limestone and marble.
Marble that has been exposed to low levels of metamorphism will have very small
calcite crystals. The crystals become larger as the level of metamorphism
progresses. Clay minerals within the marble will alter to micas and more complex
silicate structures as the level of metamorphism increases.
3/ Mineral Composition:
Marble is composed primarily of calcite, dolomite, or perhaps serpentine and
other similar minerals. The exact chemical composition of marble will greatly vary
depending on the location and the minerals or impurities present in the limestone
during recrystallization. Typically, marble is composed of the following major
constituents: 38-42% Lime (CaO), 20-25% Silica (SiO2), 2-4% Alumina (Al2O3), 1.5-
2.5% various oxides (NaO and MgO), and 30-32% various carbonates (MgCO3 and
others).
In addition to the major constituents, marble can have many different mineral
impurities of various percentages. These include: Chert, Garnet, Hematite,
Microcline, Talc, Fosterite, Muscovite, Biotite, Termolite Actinolite, and Quartz.
The presences of some of these impurities are responsible for giving marble its
color. Very pure calcite marble will always be white in color so if few impurities
are present in the marble then it will typically be white. Impurities of hematite
can give marble a reddish color. Limonite will give marble a yellow color and
serpentine will give marble a green color.
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While marble is a strong material, there are some conditions that it cannot stand.
Unlike granite, marble can’t take chemical weathering such as acid rain or any
type of acid. The marble will begin breaking down as a result of the acid. It is also
not as easily mined as granite as it is difficult to cut into large sheets.
4/ Physical Properties:
Marble occurs in large deposits that can be hundreds of feet thick and
geographically extensive. This allows it to be economically mined on a large scale,
with some mines and quarries producing millions of tons per year.
Most marble is made into either crushed stone or dimension stone. Crushed
stone is used as an aggregate in highways, railroad beds, building foundations,
and other types of construction. Dimension stone is produced by sawing marble
into pieces of specific dimensions. These are used in monuments, buildings,
sculptures, paving and other projects. We have an article about "the uses of
marble" that includes photos and descriptions of marble in many types of uses.
1/Color: Marble is usually a light-colored rock. When it is formed from a
limestone with very few impurities, it will be white in color. Marble that contains
impurities such as clay minerals, iron oxides, or bituminous material can be bluish,
gray, pink, yellow, or black in color.
Marble of extremely high purity with a bright white color is very useful. It is often
mined, crushed to a powder, and then processed to remove as many impurities as
possible. The resulting product is called "whiting." This powder is used as a
coloring agent and filler in paint, whitewash, putty, plastic, grout, cosmetics,
paper, and other manufactured products.
2/Acid Reaction: Being composed of calcium carbonate, marble will react in
contact with many acids, neutralizing the acid. It is one of the most effective acid
neutralization materials. Marble is often crushed and used for acid neutralization
in streams, lakes, and soils.
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It is used for acid neutralization in the chemical industry as well. Pharmaceutical
antacid medicines such as "Tums" contain calcium carbonate, which is sometimes
made from powdered marble. These medicines are helpful to people who suffer
from acid reflux or acid indigestion. Powdered marble is used as inert filler in
other pills.
3/Hardness: Being composed of calcite, marble has a hardness of three on the
MOH′s hardness scale. As a result, marble is easy to carve, and that makes it
useful for producing sculptures and ornamental objects. The translucence of
marble makes it especially attractive for many types of sculptures.
The low hardness and solubility of marble allows it to be used as a calcium
additive in animal feeds. Calcium additives are especially important for dairy cows
and egg-producing chickens. It is also used as a low-hardness abrasive for
scrubbing bathroom and kitchen fixtures.
4/Ability to Accept a Polish: After being sanded with progressively finer
abrasives, marble can be polished to a high luster. This allows attractive pieces of
marble to be cut, polished, and used as floor tiles, architectural panels, facing
stone, window sills, stair treads, columns, and many other pieces of decorative
stone.
5/ Durability: Marble is porous, although the pores in the surface are very tiny
and impossible to see. However, they do allow for the absorption of moisture
and other liquids which can corrode or stain the marble. Water, oils and acid rain
can affect the appearance of marble and its durability. Impurities in the marble
itself can also decrease durability of the stone.
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5/ Locality of Marble in Egypt:
Marble can be found in mountainous regions all over the world.
The marble and granite deposits are extracted from quarries which are located in
various areas: the Red Sea coasts (38%), Suez (14%), Sinai (11%), Upper Egypt
(9%), and the Nile Valley (2%).
The estimated number of quarries located all over Egypt is 500 quarries which
include registered as well as unregistered ones. The number of the quarries is
almost geographically distributed as follows: 300 marble and marbleized
limestone quarries in South Galala, 100 granite quarries in Aswan and Red Sea, 50
marble and granite quarries in Sinai, and 50 marble and marbleized limestone
quarries in North Galala.
Figure: Geographical Distribution of the Natural Stone Resources and Plants
Symbol
Description
Marble and Marbleized
Limestone
Marble and Granite
Factories
Alabaster
Source: Current Mining Development, Samih Afia, 1998.
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6/ Types of Marble in Egypt:
A recrystallized limestone that formed when the limestone softened from heat
and pressure and recrystallized into marble where a mineral change occurred. The
main consistency is calcium and dolomite. Ranges in many colors and is usually
heavily veined and shows grains. Hardness rates from 2.5 to 5 on the MOH Scale.
Marble is classified into three categories:
1. Dolomite: If it has more than 40% magnesium carbonates.
2. Magnesium: If it has between 5% and 40% magnesium.
3. Calcite: If it has less than 5% magnesium carbonates.
Table 1: The Main Marble Types by Country
Country
Main Marble Types
China
Beige Marble, Portor Gold, Green Jade, Tina Beige, Chen Green, White
Vine Black, Leopard Skin Flower, Sea Wave Flower, White Jade, and
Jinying Beige.
Egypt
Khatmeya, Golden Sinai, Silvia Dark, Silvia, Sunny, Menya, Red Breccia,
Galala, Filetto Hassana, Hashma, Zafarana, Imperial Bronze, and Samah.
France
Breche Notre Dame, Rosso Francia, Var Beige, Noir Saint Laurent, Opera
Fantistico, Corton, Elysee, and Frans Beige.
Indonesia
Mitalati, and Citatah Beige.
Italy
Bianco Teseo, Melograno, Giallo del Garda, Bianco Carrara, Portoro,
Bianco Perlino, Botticino Classico, Talli WG Green, Talli Blue, and
Gorgio Carnico.
Iran
Royal Batticino, Rosa Anarak, Aryan Royal, Bajestan, Simakan, Rosa Tea,
Langdok, and Spring Organe.
Jordan
Royal Brown, Royal Black, Royal Mink Dark, and Royal Mink Light.
Philippines
K-Beige Caramella, Teresa Beige, Capistrano, and Capistramo Light.
Portugal
Bianco Botticino, Cream Marfil, Rosa Portugal, Rosa Lagoa, Beige Solar,
Crème Champagne, Alpnina, and Azul Monica.
Spain
Marron Emperador, Perlato Svevo, Gris Malorka, Nero Marguina,
Amarilla Mares, Marron Imperial, Crema Cenia, Rojo Cehegin, Crema
Marfil Zafra, Rosa Zarzi, and Rojo Alicante.
Turkey
Bianco Botticino, Cremare Beige, Blanco Ibiza, Verde Laguna, Cremo
Mustard, Salome, Gold Anatolia, Maya Beige, Aprhrodit Light, Fantasy
Brown, Aphrodit Dark, and Rosalia.
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Main Types of Marble in Egypt
Galala
Sunny
Silvia
Samaha
Khatmia
New Silvia
Sinia-Pearl
Milly-Grey
Katrena
Desert
Emparador
Egyptian Green
Fletto
Zafarana
Breccia
Sunny-Rosa
Cleopatra
Golden-Sinia
Golden-Cream
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Table: localities of the main types of marble in Egypt
Type
Localities
Galala Marble
Suez, Aswan
Golden Cream
El-Sheikh Fadl, Red sea
Golden Sinai
Wady Feran, South Sinai
Desert (Sahara brown)
El-Qusier, Red sea
Filleto (Filleto Hassana)
El-Hassana, Sinai
Khatmia Freezing(Khatmeya)
El- Khatmeya, North Sinai, Aswan
Milly gray ( Dark gray)
Wady El-Gharandal, North Sinai
Rosa (Alba rosa)
New Valley
Samaha
Samalout, El-Menia
Silvia Freezing (Silvia)
El-Sheikh Fadl, Red sea, Aswan
Sinai pearl
Wady El-Gharandal, South Sinai, Aswan
Sunny Freezing
El-Sheikh Fadl, Red sea, Aswan
Breccia Sinai
El-Maghara, North Sinai, Aswan
Sarabajanta
El-Maghara, North Sinai
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Figure : Geographical Distribution of the Natural Stone Quarries by Type
7/ Uses of Marble:
Today, marble is a popular building material used in many architectural projects
and to create decorative effects. Because it can be obtained in many sizes and
shapes, marble tiles for walls and floors are popular in interior design. Marble has
been used throughout history in creating some of the world’s most beautiful
structures.
The ancient Greeks used marble to construct the Parthenon. The Taj Mahal is
completely covered in white marble. White marble was a favorite medium for
sculptors because of its beauty, its soft appearance and its ability to allow light to
penetrate the stone to a small degree before reflecting it back. To quote
Michelangelo: “I saw the angel in the marble, and carved until I set him free.
Source: Strategic Study on the Egyptian Marble and Granite Sector, Industrial Modernization Center, 2005.
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Very few rocks have as many uses as marble. It is used for its beauty in
architecture and sculpture. It is used for its chemical properties in
pharmaceuticals and agriculture. It is used for its optical properties in cosmetics,
paint, and paper. It is used because it is an abundant, low-cost commodity in
crushed stone prepared for construction projects. Marble has many unique
properties that make it a valuable rock in many different industries. The
photographs and captions below illustrate just a few of its varied uses.
8/ Mining:
The use of explosives in the quarrying of marble is limited because of the danger
of shattering the rock. Instead, channeling machines that utilize chisel-edged steel
bars make cuts about 5 cm (2 inches) wide and a few metres deep. Wherever
possible, advantage is taken of natural joints already present in the rock, and cuts
are made in the direction of easiest splitting, which is a consequence of the
parallel elongation of platy or fibrous minerals. The marble blocks outlined by
joints and cuts are separated by driving wedges into drill holes. Mill sawing into
slabs is done with sets of parallel iron blades that move back and forth and are
fed by sand and water. The marble may be machined with lathes and
carborundum wheels and is then polished with increasingly finer grades of
abrasive. Even with the most careful quarrying and manufacturing methods, at
least half of the total output of marble is waste. Some of this material is made
into chips for terrazzo flooring and stucco wall finish. In various localities it is put
to most of the major uses for which high-calcium limestone is suitable. Carrara in
Tuscany, Italy, is famous for being the site where all of the marble used for the
Pantheon and Trajan’s Column in Rome was quarried. Marble is mined in many
other countries around the globe as well, including Spain, Italy, Pakistan, Canada,
India and the United States.
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Figure : The Marble Supply Chain in Egypt
1: The marble quarries are
explored either by the GIS
or by random exploration.
2: Marble blocks are
extracted by different
methods such as explosives.
3: After the blocks are
extracted, they are lifted
and transported to the
marble factories.
4: The marble bocks arrive to
the factories and are left in
the storage yard.
5: The marble blocks are
cut into slabs.
6: The marble slabs are then
polished.
7: The marble slabs are
then cut into tiles of
different sizes.
8: The slabs are packed and
transported to the local
market by trucks or exported
by shipment.
9/ Economic Value:
Today, marble is a popular building material used in many architectural projects
and to create decorative effects. Because it can be obtained in many sizes and
shapes, marble tiles for walls and floors are popular in interior design.
Pricing:
The marble pricing is based on the cost and revenue analysis of the production
process starting from the extraction of marble until the product is offered to the
market. The cost is divided on two production processes: the extraction process
of marble from the quarries, and the processing process of the blocks into tiles of
Source: Author, 2011.
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different features. Each process has a different cost structure that affect the
pricing of the marble tiles in the market. Based on the data obtained from the
interviews with the factories owners, table six provides the price structure of the
blocks representing their extraction costs as well as the finished products’ price
structure which involves production process costs of tiles. In addition, the average
percentage of profit per blocks and finished products are presented in the table.
Table 6: Price Structure of Egyptian Marble Blocks and Finished Products
ITEM
Blocks
Finished Products
Cost of Capital
27%
24.3%
Cost of Manpower, Management, and Administration
1.7%
3%
Cost of Energy, Fuel & Water
6.4%
1 %
Cost of Maintenance
3%
2.7 %
Cost of Consumables
6%
23%
Taxes
11%
9%
Others
1%
1%
Net Profit
44%
36%
Total
100%
100%
The provided price structures of blocks and finished products were determined
from the data collected from the factory owners of medium and large factories. It
is important to note that there are high variations in the technology used from
one production facility to the other that can highly influence the price structure.
As mentioned previously in chapter one, the different methods used in the
marble extraction in Egypt in which there are firms that rely on traditional
extraction methods like the use of dynamite in extraction, while other firms use
advanced technology in extraction as the chain saw or diamond wires. The same
also applies to the marble processing in which the machineries used in each
production facility are not necessarily of the same cost or level of technology.
Source: Author, 2012
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Thus, the differences in the costs of capital and maintenance highly create
variations in the price structure of marble.
The marble pricing is not only based on the cost and revenue analysis, but also
it is greatly affected by the marble characteristics like: the type, quality, cut,
polish, and size of the marble tiles which have high influence on the cost of
production and price structure. These characteristics are as follows:
Marble Type: the type of marble has a great effect on the price of marble.
The more the marble type is scarce and rare, the higher its price in the
market. For instance, the Egyptian consumers demand some marble types
which are not available in Egypt like the Spanish Marron Emperador and
the Italian Botticino Classico. The consumers are willing to pay higher for
these products almost triple the price of the marble products available in
the domestic market or more.
Marble Quality: the quality of the marble is determined by its technical
and mechanical characteristics including density and water absorption
that were illustrated in the previous section. The better the quality of
marble in terms of its long term durability, the more it is priced in the
market.
Marble Tiles’ Size: there are standard sizes of marble tiles in terms of
surface size and thickness in the market. The standard thickness of the
tiles in the marble is 2 cm or 4 cm in which the 4 cm is almost double the
price of the 2 cm tiles. The standard surface shapes are mainly the
rectangle and square shapes which have various standard sizes. The
square standard sizes include: 30cm×30cm, 40cm×40cm, and
60cm×60cm; while the rectangular standard sizes comprise: 30cm×60cm,
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40cm×80cm, and 60cm×90cm. However, sometimes project contractors,
consumers, or importers demand a specific cut and size of the tiles which
require a higher cost of production. Thus, the unique sizes of the tiles
increase their market prices.
Marble Finish: there are different finishes of the marble tiles which are
based on the uses of the marble whether for flooring or cladding indoors
and outdoors. The finishes include the shinny, mat, and antique finishes
of the marble tiles. The complicated finishes are more priced like the
antique finish which requires complex production process.
After introducing the factors that influence the marble pricing, it is worth
mentioning that the marble suppliers don’t have a high influence on the
increasing the prices of the finished products or blocks due to the intense
competition in the local market. In addition, there is high competition in the
market from the cheap marble imports. Thus, the suppliers influence over the
price is very low reaching maximum 10% increase or decrease which is mainly
contributed to the specific marble characteristics which were mentioned
formerly.
After explaining the marble pricing structure, it is vital to highlight the market
prices of some selected types of marble and granite in the market for blocks as
well as finished products. The average prices ranges of marble as well as granite
selected types of blocks and slabs as obtained from several suppliers will be
provided in table seven
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Table 7: Prices of Marble Selected Types
Marble
Blocks
Slabs (2 cm)
USD/m3
USD/ m3
Sinai Pearl
265 – 300
14 – 18
Silvia or Sunny
250 – 290
13 – 17
Filetto Hassana
270 – 320
15 – 17
Galala Classic
280 – 330
14 – 18
The Egyptian marble prices are considered lower than European and Chinese
marble. This is mainly due to the fact that the costs of manpower and utilities are
lower in Egypt than in Europe or China. Thus, Egypt benefits from lower prices in
the international market which highly influence demand.
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Granite
1/ Occurrence:
What is Granite?
Granite is a light-colored igneous rock with grains large enough to be visible with
the unaided eye. It forms from the slow crystallization of magma below Earth's
surface. Granite is composed mainly of quartz and feldspar with minor amounts
of mica, amphiboles, and other minerals. This mineral composition usually gives
granite a red, pink, gray, or white color with dark mineral grains visible
throughout the rock.
The definition of "granite" varies. A geologist might define granite as a coarse-
grained, quartz- and feldspar-bearing igneous rock that is made up entirely of
crystals. However, in the dimension stone trade, the word "granite" is used for
any feldspar-bearing rock with interlocking crystals that are large enough to be
seen with the unaided eye. By this classification, rocks such as anorthosite, gneiss,
granite, granodiorite, monzonite, syenite, gabbro and others are all sold under
the trade name of "granite"
How Granite is formed
Highly durable and extremely beautiful granite is most prized of all rocks.
Traditionally widely used as a building material, especially in ancient Egypt, today
granite is more likely to be found as a countertop in a kitchen.
Granite is an igneous rock and as such is formed when molten rock, magma, cools
slowly. Magma is found between the mantle and the crust of the earth, and often
flows towards the surface of the earth. As the magma rises to the surface though
it starts to cool down, and unless it finds an escape route, could solidify as an
intrusive rock formation. The solidification though is a slow process, and where
plutons are formed, plutons being large chambers of magma, it can take millions
of years for it to actually solidify.
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The slowness of the cooling process, and also the pressure involved, ensures that
large crystals form, and therefore granite is formed. To form granite though the
magma itself must have a particular type of composition, and must in particular
be high in silicate concentration, with quartz, feldspar and mica all present.
The slowness of the process that creates granite ensures that it is one of the
hardest of all rocks, and both feldspar and quartz can be harder than
manufactured steel.
The formation of granite means that granite can be found in a range of colours,
from pink through to grey and black. The colour itself is dependent upon the
mineralogy of the granite, and in particular the chemistry composition of the
feldspar. Feldspar is natural light in colour, and a higher concentration of it will
result in pink granite.
Today granite is quarried, where huge blocks are cut away and then cut into
thinner slabs. It is these slabs that are used by kitchen makers.
Granite though can be seen all around the world in its natural environment. The
hardness of granite means that it outlasts many of the metamorphic rocks that
surround it as it forms. As the landscape changes, the earth’s surface can erode
leaving granite outcrops, tors or rounded massifs. This creates distinct landscapes
the likes of Dartmoor and Exmoor in England.
Granite has a natural beauty that ensures that when found in the natural
environment it can be an awe inspiring site. This beauty though can be
transported into the home, with granite work surfaces high in demand. When in
the kitchen though it is easy to overlook the millions of years, and the process
involved, that it takes to actually form granite.
The Best-Known Igneous Rock:
Granite is the best-known igneous rock. Many people recognize granite because it
is the most common igneous rock found at Earth's surface and because granite is
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used to make many objects that we encounter in daily life. These include counter
tops, floor tiles, paving stone, curbing, stair treads, building veneer, and cemetery
monuments. Granite is used all around us - especially if you live in a city.
Granite is also well-known from its many world-famous natural exposures.
Multiple Definitions of Granite:
The word "granite" is used in a variety of ways by different people. A simple
definition is used in introductory courses; a more precise definition is used by
petrologists (geologists who specialize in the study of rocks); and, the definition of
granite expands wildly when used by people who sell decorative stone such as
countertops, tile, and building veneer.
These multiple definitions of granite can lead to communication problems.
However, if you know who is using the word and who they are communicating
with, you can interpret the word in its proper context. Three common usages of
the word "granite" are explained below.
A) Introductory Course Definition
Granite is a coarse-grained, light-colored igneous rock composed mainly of
feldspars and quartz with minor amounts of mica and amphibole minerals. This
simple definition enables students to easily identify the rock based upon a visual
inspection.
B) Petrologist's Definition
Granite is a plutonic rock in which quartz makes up between 10 and 50 percent of
the felsic components and alkali feldspar accounts for 65 to 90 percent of the
total feldspar content. Applying this definition requires the mineral identification
and quantification abilities of a competent geologist.
Many rocks identified as "granite" using the introductory course definition will
not be called "granite" by the petrologist - they might instead be alkali granites,
granodiorites, pegmatites, or aplites. A petrologist might call these "granitoid
22
rocks" rather than granites. There are other definitions of granite based upon
mineral composition.
The chart below illustrates the range of granite compositions. From the chart you
can see that orthoclase feldspar, quartz, plagioclase feldspar, micas, and
amphiboles can each have a range of abundances.
C) Commercial Definition
The word "granite" is used by people who sell and purchase cut stone for
structural and decorative use. These "granites" are used to make countertops,
floor tiles, curbing, building veneer, monuments, and many other products.
In the commercial stone industry, granite is a rock with visible grains that is
harder than a marble. Under this definition, gabbro, basalt, pegmatite, schist,
gneiss, syenite, monzonite, anorthosite, granodiorite, diabase, diorite, and many
other rocks will be called "granite." The collection of images here illustrates the
range of rocks that might be called "granite."
Granite composition chart: This chart illustrates the generalized mineral
composition of igneous rocks. Granites and rhyolites (compositionally equivalent
to granite but of a fine grain size) are composed mainly of orthoclase feldspar,
quartz, plagioclase feldspar, mica, and amphibole.
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3/ Mineral Composition:
Granite is distinguished from other intrusive igneous rocks on the basis of the
minerals it contains. The major component minerals of granite are quartz,
potassium feldspar (orthoclase) and muscovite mica. Lesser quantities of sodium-
rich feldspar (plagioclase) and iron- and magnesium-bearing (ferromagnesian)
minerals, such as hornblende and biotite mica, are generally present. By
definition, granite contains at least 10% free quartz (SiO2) by volume; silica in the
quartz and other minerals typically exceeds 70% by volume. The extrusive igneous
rock that formed at the surface from cooling of lava with the same mineralogy
and chemistry as granite is called rhyolite.
To petrologists, earth scientists specializing in rocks; granite isn’t a single rock
type; it’s a group of closely-related rocks. The granite group includes pegmatite,
aplite, syenite, granodiorite, monzonite, latite and quartz monzonite, among
others. While all members of the granite group have the same texture and fall
within a set range of chemical compositions, they can be differentiated on the
basis of the minerals present. The relative proportions of different feldspars
(orthoclase vs. plagioclase; alkali vs. calcium) and quartz content are the most
common criteria for differentiation. In common usage, however, granite simply
refers to the rocks that can be identified as part of the granite group without
chemical or mineralogical analysis.
The resulting granite will likely have been made primarily from quartz, different
feldspars, and biotite, however, it can also have a variety of other minerals and
oxides present. Quartz content can range from 10-60%, while the feldspar
content typically ranges from 65-95%, and biotite content is around 10-15% in
most granite.
The exact chemical composition will vary greatly but there is an average chemical
composition for granite. This composition is as follows: 70.18% silicon dioxide
(SiO2), 14.47% aluminum oxide (Al2O3), 4.11% potassium oxide (K2O), 3.48%
sodium oxide (Na2O), 1.99% calcium oxide (CaO), 1.78% iron (II) oxide (FeO),
1.57% iron (III) oxide, 0.88% magnesium oxide (MgO), 0.84% water (H2O), 0.39%
titanium dioxide (TiO2), 0.19% diphosphorus pentoxide (P2O5), and 0.12%
manganese oxide (MnO).
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The chemical composition as well as the formation of granite inside the Earth’s
surface produces an incredible material that is valued for its looks and physical
properties. It has even started replacing marble because of its more durable
qualities and resistance to weather and acid rain. Though a very common rock,
granite is far from ordinary.
4/ Physical Properties:
1/Color: Granite comes in many different colors thanks to the composition and
minerals within the rock. Colors range from pink to gray and black. There are no
two slabs of granite that are alike, making each granite countertop something
completely unique. Fresh samples of granite are generally pink or gray as a result
of the large amounts of quartz and feldspar present. The color can range from red
to white, generally with a “speckled” appearance due to the presence of dark
mineral grains.
2/Hardness: Granite is one of the hardest substances in the world. In fact, the
only thing that is harder than granite is diamonds. This is what makes granite so
sought after as a countertop. For the simple fact that it is extremely durable and it
cannot be damaged by scratching. You can cut on a granite countertop because it
is so hard and durable.
3/ Texture: True granite typically has an even texture of similar-sized mineral
grains, though some bodies contain scattered larger crystals; a texture known as
porphyritic. Porphyritic rocks are believed to represent two-stage cooling: first,
slow cooling allowing large crystals to form, followed by more rapid cooling that
creates the less-coarse matrix or groundmass. Orbicular granite is another, more
unusual type oy porphyritic granite distinguished by large spherical inclusions.
Orbicular granite is mined in Australia and Finland.
Granite’s hardness and even texture make it an attractive candidate for building
stone. In recent years, so-called “granite” countertops have been popular options
for new and remodeled kitchens. Not all granite used in building is actually
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granite, however; to building stone vendors the term simply means that the rock
has visible mineral grains and is harder than marble. Consequently, “granite” used
in countertops includes almost any intrusive igneous rock or even coarse-grained
metamorphic rocks. Highly polished slabs of granite (both true and “granite”) are
also used to face buildings and for decorative elements in construction. Rough-cut
granite blocks have been used for road and building construction for thousands of
years. The reddish-colored gravel used in many paths and walkway is often
crushed, weathered granite.
The other intrusive rocks with a granular texture similar to granite’s range from
the rare anorthosite (found on the moon and in the Earth’s mantle) though nearly
black gabbro to diorite. These rocks are differentiated on the basis of the minerals
they contain: for instance, gabbro (the intrusive equivalent of basalt) contains no
quartz or orthoclase feldspar, instead it is almost entirely ferromagnesian
minerals and plagioclase (sodium and calcium) feldspar. Closer to granite, diorite
(intrusive equivalent of andesite) contains mainly feldspars plus less than 10%
quartz.
In all intrusive igneous rocks such as granite, the individual mineral crystals create
an interlocking texture, much like a three-dimensional jigsaw puzzle. The
interlocking texture and random distribution of minerals is important, for this
texture defines the difference between igneous granite and metamorphic gneiss,
which may be composed of much the same group of minerals. The texture of
gneiss is typically foliated, which gives a sample a layered appearance. In gneiss
and other foliated rocks, minerals are concentrated in layers rather than
randomly distributed.
5/ Locality:
Granite and other igneous rocks are abundant in the Earth’s crust. More than 95%
of the Earth’s crust consists of igneous rocks formed from lava ejections. Granite
often forms rounded hills scattered over a hillside, and is major component of the
mountain ranges of the world. Granite is usually found at convergent plate
boundaries where part of the ocean lithosphere submerges underneath a
continental plate boundary. The process generates enough pressure and melting
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points to create granite. Fractionation created all the world’s volcanic arcs and
continents.
Most introductory geology textbooks report that granite is the most abundant
rock in the continental crust. At the surface, granite is exposed in the cores of
many mountain ranges within large areas known as "batholiths," and in the core
areas of continents known as "shields."
The large mineral crystals in granite are evidence that it cooled slowly from
molten rock material. That slow cooling had to have occurred beneath Earth's
surface and required a long period of time to occur. If they are today exposed at
the surface, the only way that could happen is if the granite rocks were uplifted
and the overlying sedimentary rocks were eroded.
In areas where Earth's surface is covered with sedimentary rocks, granites,
metamorphosed granites, or closely related rocks are usually present beneath the
sedimentary cover. These deep granites are known as "basement rocks."
Localities of Granite in Egypt:
Granite is found mainly in three main localities ... Eastern Desert, South Sinai, and
North of Aswan.
Especially at:
1/ Group of Farayda Mountains.
2/ Meabesah, Aadar Kaka and Ess Mountains (Daeeb & Haseeb Valleys).
3/ Elba and Shendieb Mountains (south east coast of Red Sea).
4/ Nagras, Selaya, Um Raseen and Adar Eeweib Mountains.
5/ Homrat El-Wegood and Homrat Makod Mountains.
6/ Fiery back area (Southern back), at South Sinai.
6/ Qena-Qusier road Mountains.
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6/ Types of Granite in Egypt:
We differentiate between granite according to mineral compositions and some
physical properties such as color, texture and grain size ....etc.
Figure: differentiate between granite rocks according to the relative abundance of
feldspars (K-Na-Ca) and quartz
Granitic rocks: This triangular
diagram is a classification method
for granitic rocks. It is based upon
the relative abundance of feldspars
(K-Na-Ca) and quartz. Mafic
elements are not considered. It is
modified after a classification chart
prepared by the International Union
of Geological Sciences. Image and
modification by the United States
Geological Survey.
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Figure: Main Egyptian Granite Types
Source: Strategic Study on the Egyptian Marble and Granite Sector, 2005.
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7/ Uses of Granite:
Granite was widely used in ancient times. The Red Pyramid in Egypt is named
after the reddish hue of its stones, which is made of granite stones. The Great
Pyramid of Giza contains within an enormous granite sarcophagus. In India, many
structures and life-size animal statues were carved using granite stones.
According to jmu.edu, the Earth began with a composition similar to the one seen
in the Moon, and from that beginning, all other rocks have evolved through a
series of fractionation. From this theory, it is thought that the parent rock present
at the time of the Earth’s formation gave rise not only to igneous rocks, but
sedimentary and metamorphic rocks, as well.
Granite has been used for thousands of years in both interior and exterior
applications. Rough-cut and polished granite is used in buildings, bridges, paving,
monuments, and many other exterior projects. Indoors, polished granite slabs
and tiles are used in countertops, tile floors, stair treads, and many other practical
and decorative features.
High price often reduces the popularity of a construction material, and granite
often costs significantly more than man-made materials in most projects.
However, granite is frequently selected because it is a prestige material, used in
projects to produce impressions of elegance, durability, and lasting quality.
Granite is also used as a crushed stone or aggregate. In this form it is used as a
base material at construction sites, as an aggregate in road construction, railroad
ballast, foundations, and anywhere that a crushed stone is useful as fill.
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31
32
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8/ Mining:
Granite is the rock most often quarried as a "dimension stone" (a natural rock
material that has been cut into blocks or slabs of specific length, width, and
thickness). Granite is hard enough to resist most abrasion, strong enough to bear
significant weight, inert enough to resist weathering, and it accepts a brilliant
polish. These characteristics make it a very desirable and useful dimension stone.
Most of the granite dimension stone produced in the United States comes from
high-quality deposits in five states: Massachusetts, Georgia, New Hampshire,
South Dakota, and Idaho.
Figure: The Traditional Marble Extraction Process in Egypt
Source: Strategic Study on the Egyptian Marble and Granite Sector, Industrial Modernization Center, 2005.
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9/ Economic Value:
Granite is similar to the marble from the extraction and uses, so there are slight
differences in prices.
Table 7: Prices of Granite Selected Types
References:
1/ The Geology of Egypt [Rushdi Said, 1990].
2/ ECONOMIC AND FINANICAL VALUATION OF THE MARBLE INDSUTRY IN EGYPT(By Farah
Ahmed Fouad Abdel Meguid Haggag, The American University in Cairo)
3/
4/
Granite
Blocks
Slabs (2 cm)
USD/m3
USD/ m3
Red Aswan
450 -520
32 – 36
Nero Aswan
700 – 850
40 – 55
Gray Granite
300 – 380
29 – 35
Rosa Aswan
260 – 380
25 – 28
White Halayeb
460 – 500
32 – 36
Source: Strategic Study on the Egyptian Marble and Granite Sector, 2005.
