This gives the information about the stones origin, classification, quality,quarrying, blasting and dressing.

1. STONES
By
Rajitha.

2. STONES:
Qualities of good building stones
Stone quarrying
Tools for blasting
Process of blasting
Precautions in blasting
Dressing of stones
Common building stones in India

3. STONES
 Rock
A solid mass consisting of different types of
minerals, which form the earths crust is known as
Rock.
These minerals are not homogeneous.
It has no definite shape and structure.
 Stone:
It is a naturally available construction material.
It is quarried and extracted from the rock.
The properties of stone depends upon the mother
rock, from which it is extracted.
The extracted stones can be make in different sizes
and shapes to full fill the needs of the structure.

4. CLASSIFICATION OF ROCKS

5. IGNEOUS ROCKS
 Igneous rocks are formed by the cooling of
highly heated molten fluid material called as
Magma.
These rocks may from under the earth or on the
surface of the earth.

6. Intrusive Igneous Rocks
 They are formed when magma solidifies below
the earth’s surface.
 The rate of cooling below the earth’s surface is
very slow which gives rise to the formation of
large crystals in the rocks.
 That is, the mineral grains of intrusive igneous
rocks are very large.
 Deep-seated intrusive igneous rocks are called
as Plutonic rocks and shallow depth intrusive
igneous rocks are called as Hypabyssal Rocks.
 Eg: Granite, dolerite, etc.

8. Extrusive Igneous Rocks
 They are formed by the cooling of the lava on
the earth’s surface.
 As lava cools very rapidly on the surface, the
mineral crystals forming extrusive igneous
rocks are very fine.
 These rocks are also called as Volcanic Rocks.
 Eg: Gabbro, Basalt, etc.


10. SEDIMENTARY ROCKS
 The existing rocks (Igneous rock) are
disintegrated due to constant exposure due to
weathering agencies like heat, wind, rain, and
snow.
 All the disintegrated particles are transported
from mother rock to other places by water and
wind , which are alternately deposited as layers at
the bottom of lakes, rivers and oceans. During the
course these layers are consolidated, in the
presence of wind and other chemical agents.This
process of consolidation turns the loose particles
into hard mass like rock.This type of rock is called
as sedimentary rock.
 Ex: Gypsum, Sand stone, Gravel.

11. Clastic sedimentary rocks
 Clastic sedimentary rocks are rocks
composed predominantly of broken pieces
or clasts of
older weathered and eroded rocks.
 Ex: conglomerate

13. Chemical sedimentary rock
 Chemical sedimentary rock is formed when
minerals, dissolved in water, begin to
precipitate out of solution and deposit at the
base of the water body.

15. Organic sedimentary rocks
 Organic sedimentary rocks form from the
accumulation and lithification of organic
debris, such as leaves, roots, and other plant
or animal material.
 Ex:Coal

17. METAMORPHIC ROCKS:
 when Igneous and Sedimentary rocks are
changed in character due to
pressure and temperature then metamorphic
rocks formed.These rocks are found deep
within earth.
 Slate: Clay becomes slate after
metamorphosis [Texture = Foliated]
 Marble: Limestone becomes marble after
metamorphosis [Texture = Non-Foliated]

19.  There are two basic types of metamorphic
rocks.
 Foliated metamorphic rocks such
as gneiss, phyllite, schist, and slate have a
layered or banded appearance

21.  Non-foliated metamorphic rocks such
as hornfels, marble, quartzite,
and novaculite do not have a layered or
banded appearance.

23. PHYSICAL CLASSIFICATION:
 This type of classification is based on general
structure of rocks. According to this classification
the rocks are classified into three types–
 a. Stratified rocks:These rocks possess planes of
stratification or cleavage and can be easily split
up along the planes.This type of rocks show a
layered structure in their natural environment.
Example-Gravel, Sand Stone, Limestone,
Gypsum etc.

25.  b. Unstratified rocks:The structure of this
type of rocks may be crystalline or granular.
This type of rocks don’t show any sign of
strata.
Example-granite and marble.
 c. Foliated Rocks: Foliated rock is a
metamorphic rock that has layers. In other
word, when a metamorphic rock’s texture is
some how arranged in planes that is called
foliated rocks.
Example-metamorphic rocks

27. CHEMICAL CLASSIFICATION:
 According to this classification rocks are classified
into three types.
 a. Siliceous rocks: In these rocks, silica is
predominates.The
 rocks are hard; durable and not easily effected by
weathering
 agencies. Ex: Granite, Quartzite, etc.
 b. Argillaceous Rocks: In these rocks, clay
predominates.The rocks may be dense and
compact or may be soft. Ex: slates, Laterites etc.
 c. Calcareous rocks: In these rocks, calcium
carbonate predominates.The durability to these
rocks will depend upon the constituents present in
surrounding atmosphere. Ex: Lime Stone, marble
etc,.

28. Qualities of good building
stones:
 Appearance.
 Strength.
 Structure
 Texture
 Durability
 Hardness.
 Toughness.
 Porosity and
absorption.
 Workability.
 Seasoning.
 Dressing
 Specific gravity
 Resistance to fire.
 Cost

29. Appearance:
For face work it should be uniform in colour
and texture.

30.  Strength:
A stone should be strong and durable to
withstand the loads.
 Structure:
A broken stone should not be dull in
appearance and should have uniform texture
free from cavities, cracks, and patches of loose
or soft material. Stratifications should not be
visible to naked eye.

31.  Texture:(Arrangement of minerals)
It is preferred to have building stones with
fine crystalline compact structure as those
are more stronger.
 Durability:
It should be able to withstand and resist the
action of the atmosphere such as rain, wind,
temperature etc (depends upon chemical
composition and physical structure).
 Hardness.
It is the resistance of stone to abrasive forces
caused by much wear and friction as in
floors, pavements

32.  Toughness.
It is a measure of the impact that a stone can with
stand. Stones used at places subject to vibrations of
machinery and to moving loads should be tough.
Stones used in the construction of roads should be
hard and tough.
 Porosity and absorption.
A good building stone should be less porous.
The stone should not absorb water more than 5%
either in the volume of water or in weight, when it
immersed in water for 24 hours.
 Workability:
Stone should be workable so that cutting, dressing
and bringing it out in the required shape and size
may not be uneconomical.

34.  Seasoning:
The stone should be well seasoned.
Good stones should be free from the quarry sap.
Lateritic stones should not be used for 6 to 12
months after quarrying.They are allowed to get
rid of quarry sap by the action of nature.This
process of removing quarry sap is called
seasoning.
 Dressing
Giving required shape to the stone is called
dressing. It should be easy to dress so that the
cost of dressing is reduced.
Stones possessing dressing properties are weak in
strength and durability.

35.  Specific gravity
The more the specific gravity of stone, the more
heavier and stronger the stone is.
Therefore stones having higher specific gravity values
should be used for the construction of dams, retaining
walls, docks and harbors.The specific gravity of good
building stone is between 2.4 and 2.8.
 Resistance to fire:
A Building stone should be free from minerals such as
calcium carbonate and oxides of iron and also, the
minerals present in stones should not have different co-
efficient of thermal expansion. Building Stones should
also be able to resist high temperature.
 Cost
The cost of good building stone is not uneconomical.

36. Stone quarrying
 Stones occur in the form of natural
rock masses or layers on the surface.
The process of extraction of suitable
stones from their natural rock beds or
layers is commonly called Quarrying
of Stones.

38. Selection of Quarrying Site
 Availability of sufficient quantity and required
quality of stones.
 Proper transportation facility from quarry to
roads, railways , etc…
 Easy drainage of rain water from the quarry pit at
low cost.
 Availability of local labor easily.
 Easy availability of clean water in sufficient
quantity for a longer period.
 No presence of permanent structures.
 Availability of site for dumping refuse.
 Availability required power station, required
machinery for cutting, crushing etc..

39. Methods of quarrying
1. Quarrying with hand tools.
2. Quarrying with channeling machine.
3. Quarrying by blasting.

40. Quarrying with hand tools
 Digging (or) excavating.
 Heating.
 Wedging.

41. Digging (or) excavating.
 The stones are excavated with the help of
pickaxes, hammers, shovels, chisels,
etc…useful for soft stones.

43. Heating.
 The top surface of rock is heated by placing
wood with fuel on it.The fire will be allowed
for some hours and the top surface gets
heated and separates from the rock.This
separated portion is removed by pick axes,
crowbars etc.

45. Wedge Method of Quarrying
 This method is applicable when the rock
contains cracks or joints in it. Steel wedges or
steel points are put in these cracks or fissures
and hit them with hammer.
 Then the rock portion separates from parent
rock. If natural cracks are not there, then
artificial holes are drilled in the rock and
wedging is done.

47. Quarrying with channeling
machine
 Machine quarrying is done by using channeling
machines in the site.This type of machine is driven
by steam, compressed air or electricity.
 A groove is made using this machine around the
rock and the horizontal holes are drilled underneath
the block. Hence, the block gets separated from its
bed.
 A large groove of 24-meter length and 50 to 75 mm
width and with a depth about 2 to 3.7 meter can be
made using channeling machine. So, larger blocks
of stones can be obtained using this method.
 Marbles, lime stones, etc. are quarried using
machine quarrying.

49. Quarrying by blasting
 The main purpose of blasting is to obtain small
stones which are used as ballast for railway
works, aggregate in concrete works etc..
 In this method explosives are used to separate
the stones from parent rock.This process is
applied in case of hard stone or hard rock which
does not contain any cracks or fissures.
 The holes are drilled in the rock and explosives
are arranged in the holes and blasted with proper
safety measures.The stones obtained through
this process are not larger in size.

50. TOOLS FOR BLASTING
1.Dipper
2.Jumper
3.Priming needle
4.Scraping spoon
5.Tamping bar

51.  Dipper- Used to drill hole to the required depth.
 Jumper- Used to make blast hole & more
effective in boring a nearly vertical hole.
 Priming needle- Used to maintain the hole
while tamping is done & is in the form of a thin
copper rod with a loop at one end.
 Scraping spoon- Used to remove dust of
crushed stone from blast hole.
 Tamping bar- Used to tamp the material while
refilling a blast hole.

53. Explosives used in blasting
 Blasting powder
 Dynamite
 Gun cotton
 Blasting gelatine
 Cordite
 Gelignite

54. Precautions in blasting
 The blasting should not be carried out in late
evenings
 The danger zone should be marked with red
flag
 First aid should be made available
 Explosive should be stored and handled
carefully.
 Detonators and explosives should not be kept
together.

55. Dressing of stone
 Stones extracted from quarry or irregular in
shape and they are not useful for construction
without dressing. Depending up on the type of
stone masonry and also for special
purposes…the stones are cut into suitable size
and required shape and surface.
 Necessity of dressing
(i) to obtain the pleasing appearance
(ii) to obtain proper bedding with good motor
joints
(iii) to obtain special shapes for arches coping
pillars etc..

56. Dressing tools

57. Different Finishes of Stones
 Axed finish
Axe is used to get the required surface of hard
stones like granite etc.This finish is called as
axed finish.

58. Boasted Finish of Stones
 Boasted finish is also called as droved finish.
This type of finish contains intermittent
parallel lines which are horizontal or vertical
or inclined.This finish is obtained by a tool
called boaster which have an edge of width
about 60 mm.

59. Combed Finish of Stones
 Combed finish is suitable for soft stones. Steel
comb of sharp teeth is dragged on the surface
of soft stone.This is done in all directions of
stone surface.This is also called as dragged
finish.

60. Circular Finish of Stones
 The surface of stone is made into rounded
shape. Circular finished stones are mainly
used for columns.

61. Molded Finish for Stones
 Using machines or tools, stone surfaces are
molded into desired shapes which also provide
good appearance to the work.

62. Polished Finish for Stones
 Polished finish is provided for marbles,
granites etc. which are mostly used as floor
tiles. Polishing can be done by hand or
machines.

63. Common building stones in
India
 GRANITE:
Classification: Igneous rock
Characteristics: Specific gravity-2.63 to 2.75
water absorption- <1%
Compressive strength-77 to 130N/mm2
Uses: Most suitable for important engineering
works such as abutments, dams, lighthouse,
bridges, piers, etc..,

64.  MARBLE:
Classification: Metamorphic rock
Characteristics: Specific gravity-2.72
water absorption- <3%
Compressive strength-50 to 70N/mm2
Uses: It is mainly used for ornamental works,
preparation of furniture(flower vases, benches,
chairs etc..,),table tops, stair cases, columns,
beams. It is widely used as a face of walls
especially in religious places.

65.  LIME STONE:
Classification: Sedimentary rock
Characteristics: Specific gravity-2.0 to 2.75
water absorption- <1%
Compressive strength-55N/mm2
It is tough but soft enough to cut.
Uses: Suitable for flooring and roofing and in
manufacturing of lime and cement.