Stones Flashcards
Basis of Classification of Rocks
i. Geological Classification
ii. Physical Classification
iii. Chemical Classification
Geological Classification of Rocks
i. Igneous
ii. Sedimentaryd
iii. Metamorphic
What are igneous rocks
Rocks of volcanic origin, formed due to solidification of molten mass
Examples of Igneous Rocks
Granite, Basalt, Dolerite, Trap
What are Sedimentary rocks
Rocks formed due to deposition of sediments (disintegrated rock pieces, clay, sand, silt, etc)
What are Sedimentary rocks aka?
aqueous or stratified rocks
What are igneous rocks aka?
effusive rocks
Examples of Sedimentary rocks
Sandstone, Limestone, Chalk, Lignite, shale, gypsum
What are Metamorphic rocks
Rocks formed from igneous or sedimentary rocks as a result of the action of
the earth movements, temperature changes, liquid pressures, etc
Examples of Metamorphic rocks
Slate, Gneiss, Marble, Quartz
Physical Classification of Rocks
i. Stratified Rocks
ii. Unstratified Rocks
iii. Foliated Rocks
What are stratified Rocks
Rocks that show distinct layers along which the rocks can be split. (layers appear upon Cleavage)
Examples Stratified Rocks
sandstone, limestone, shale, marble
What are Unstratified Rocks
Rocks that do not show any stratification and cannot be easily split into thin layers. (Uniform distribution of minerals upon cleavage)
Examples of Unstratified Rocks
granite, basalt, trap
What are Foliated Rocks
Rocks that have a tendency to split up only in a definite direction
Examples of foliated rocks
Slate, Gneiss, all metamorphic except Quartzite and marble
Chemical Classification of Rocks
i. Argillaceous Rocks
ii. Silicious Rocks
iii. Calcarious Rocks
What are Argillaceous Rocks
Rocks with clay (Al2O3) as principle constituent
Characteristics of Argillaceous Rocks
Hard and Brittle
Examples of Argillaceous Rocks
Slate, Laterite
What are Silicious Rocks
Rocks with Silica (SiO2) as principle constituent
Characteristics of Silicious Rocks
Very hard and Durable
Examples of Silicious Rocks
granite, basalt, trap, quartzite, gneiss, syenite
What are Calcarious Rocks
Rocks with Lime (Ca(OH)2) as principle constituent
Examples of Calcarious Rocks
limestone, marble, dolomite
What is Stone Quarrying
The operation involved in the production of natural stone is the quarrying process
What is a Quarry
The open part of the natural rock from which useful stone is obtained
Criteria for Quarry site
i. Sufficient quantity of the stone of desired quality
ii. Proper transportation facilities
iii. Cheap local labour
iv. Problems associated with drainage of rain water
v. Location of important and permanent structures in the vicinity
vi. Site for dumping refuse
What is Natural Bed of Stone
It is the original bed, plane or position occupied by a stone during its formation in a sedimentary
rock
What is Seasoning of Rocks
The process of removing/extracting water from rock is called seasoning of rocks
What is Quarry Sap
A freshly cut stone carries some natural moisture known as quarry sap. It is mineral solution.
How long does it take for Seasoning of Rocks
6-12 months
What is Dressing of Stone
The working of quarried stone into the shape and size required for use.
Characteristics of a Good Building Stone
i. Appearance: fine, compact texture, light color preferred
ii. Structure: uniform texture free from cavities, cracks
iii. Compressive Strength: >100N/sq. mm
iv. Hardness: >17 (Dorry’s Test for Hardness) (Moh’s Scale => 1-10)
v. Weight: It is an indication of the porosity and density.
vi. Toughness: The measure of impact that a stone can withstand is defined as toughness (>19, impact test for toughness index)
vii. Water Absorption: <0.6%
viii. Weathering Resistant (from wind, rain, frost action, temp)
ix. Fire Resistance and insulation
x. Specific Gravity: >2.6
xi. Good Seasoning
State Common Building Stones in India
i. Marble
ii. Granite
iii. Laterite
iv. Basalt and Trap
v. Gneiss
vi. Limestone
vii. Slate
viii. Sandstone
Characteristics of Marble
- Metamorphic
- Color: White
- Specific Gravity 2.6
- Compressive Strength 71N/sq mm
- Can polish the surface for shining
- Hard and compact
- Usage: Aesthetic Purpose, Flooring, etc
Characteristics of Granite
- Igneous
- Color: White, pink or Grey
- Specific Gravity 2.6-2.7
- Compressive Strength : 75-130 N/sq mm
- Weight 26-27 KN/cu mm
- Water Absoption <1%
- Hard and Durable
- Usage: Steps, walls, columns and for foundation
Characteristics of Basalt and Trap
- Igneous
- Color: Black
- Specific Gravity 3
- Compressive Strength: 150-185 N/sq mmm
- Weight 18-29 KN/cu mm
- 40-60% silica
- Hard and Tough
- Usage: Road material, concrete aggregates, foundation rocks
Characteristics of Gneiss
- Metamorphic
- Stratified Granite
- Color: Grey
- Specific Gravity 2.69
- Compressive Strength 206N/sq mm
- Strong and Durable
- Easy to work
- Usage: Street Paving, Stone masonary
Characteristics of Limestone
- Sedimentary
- Main Constituent: Calcite
- Color: White (pure)
- Specific Gravity 2-2.75
- Compressive Strength 54N/sq mm
- Tough but soft enough to cut
- Usage: Flooring, paving, roofing, manufacture of lime and cement
Characteristics of Slate
- Metamorphic
- From Shale
- Color : Black/Grey
- Specific Gravity 2.89
- Compressive Strength 77-210 N/sq mm
- Hard and Tough
- Can be split into thin slabs
- Usage: roof covering, flooring, Damp-proofing
Characteristics of Sandstone
- Sedimentary
- Constituent of Quartz and other minerals
- Color: Tan
- Specific Gravity 2.65-2.95
- Compressive Strength 64N/sq mm
- Weight 20-22 kN/cu mm
- Easy to work and dress
- Usage: Steps, flooring, walls, column, road material, ornamental curving
