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Limestone
Limestone
is calcareous sedimentary rocks formed at the bottom of lakes and seas
with the accumulation of shells, bones and other calcium rich goods.
It is composed of calcite (CaCO3). The organic matter upon which it
settles in lakes or seas, are preserved as fossils. Over thousands and
millions of years, layer after layer is built up adding weight. The
heat and pressure causes chemical reaction at the bottom and the
sediments turn into solid stone, the limestone.
The rock which contain more than 95% of calcium carbonate is known as
high-calcium limestone. Recrystallised limestone takes good polish and
is usually used as decorative and building stone.
A part of calcium molecules if being replaced by magnesium, it is
known as magnesium lime stone or dolomite limestone.
Limestone that will take a polish are considered marbles by most
people, but technically, if there are still shells visible or the
structure is not crystalline, it is still a limestone.
Physical Properties of Limestone
| Hardness
|
3 to
4 on Moh's Scale |
| Density |
2.5
to 2.65 Kg/m3 |
| Compressive
Strength |
1800
to 2100 Kg/cm2 |
| Water
Absorption |
Less
than 1% |
| Porosity
|
Quite
low |
| Weather
Impact |
Resistant |
Chemical
Properties of Limestone
| Lime (CaO) |
38-42% |
| Silica
(SiO2) |
20-25%
|
| Alumina
(Al2O3) |
2-4%
|
| Other
Oxides like Na, Mg |
1.5
to 2.5% |
| Loss
On Ignition (LOI) |
30-32%
|
Note
:- Limestone, like marble and other calcareous stones, are
referred to as acid sensitive. Calcareous stones are readily dissolved
in acid, therefore acidic products should not be used on limestone and
marbles.
Uses of Limestone
- Flooring
- Wall
cladding
- Vanity
tops
- Furniture
- Cement
Production
- Refining
Metals
- Blackboard
chalk
Ocurrances
of Limestone
| Texas |
Lampasas
River area |
| India |
Khasi,
Jayantia and Garo Hills of Meghalaya
Satna limstone belt, Madhya Pradesh |
| United Kingdom |
United
Kingdom Alston, Cumbria
Stockfield, Northumberland
Doncaster, South Yorkshire
Moelfre, Gwynedd
Ancaster, Lincolnshire
Lincoln, Lincolnshire
Oakham, Leicestershire
Peterborough, Northamptonshire
Grantham, Lincolnshire
Stamford, Lincolnshire
Linby, Nottinghamshire |
| New Zealand |
Airedale
Road Weston |
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