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Granite
Granite,
from igneous rock, is a very hard, crystalline, and primarily composed
of feldspar, quartz accompanied by one or more dark minerals. It is
visibly homogeneous in texture.
The term "Granite" means "grain" in Latin word "Granum"
because of its granular nature.
Granite is the hardest building stone, and granite slabs and granite
tiles occupy a prominent place among dimensional stones. Due to its
hardness, resistance to weathering, capability to take mirror polish,
fascinating colors and textural patterns, granite slabs and granite
tiles are extremely popular.
The principal characteristics of granite also include high load
bearing capacity, crushing strength, abrasive strength, amenability to
cutting and shaping without secondary flaws, ability to yield thin and
large slabs and - above all - durability.
Due to highly dense grain, it is impervious to stain. Polished
granite slabs and granite tiles have achieved a special status as
building stones globally. Granite is also used for wall cladding,
roofing, flooring, and a variety of other interior and exterior
applications.
India is one of the largest producers of granites blocks and
processed granite slabs and granite tiles. Granites from leading
Indian exporters are listed here.
Physical Properties of Granite
Physically, commercial granites are Hard, Compact rocks with fine to
coarse grains of metamorphic or igneous origin.
| Hardness
|
6 to
7 on Moh's Scale |
| Density
|
2.6
to 2.8 Kg/cm3 |
| Compressive
Strength |
140
to 210 N/mm2 |
| Modulus
of Rupture |
15 to
25 N/mm2 |
| Water
Absorption |
0.1-0.6%
|
| Average
Wear |
Less
then 1% |
| Porosity |
Quite
low |
| Weather
Impact |
Resistant |
Chemical Properties of Granite
Chemically, they are igneous/metamorphic rocks composed of quartz,
feldspar & ferromagnesian minerals like kriolite, chlorite,
garnet, etc. A typical granite will have following chemical
composition:
| Silica
(SiO2) |
70-75%
|
| Al2O3 |
10-15%
|
| CaO+MgO |
Less
then 0.5% |
| FeO +
Fe2O3 |
2-4% |
| Alkalies |
4-6% |
| TiO2 |
Less
then 0.5% |
| Loss
On Ignition (LOI) |
Less
then 0.5% |
Uses
of Granite
- Roadstone,
building blocks, but has poor resistance to fire as it crumbles when
exposed to intense heat.
- Traditionally
the main use of black granite is in tombstones and other monumental
items, and to a lesser extent for various types of counters,
especially in the financial world, decorative applications, elegant
trimmings and luxury floorings.
- Stones
on bolo cord slides and pendants, paperweights, bookends, lazy susan
turntables, etc.
Ocurrances
of Granite
| India |
Chimakurthy
Mandal, Prakasham Dist, Andhra Pradesh
Elandur, Kollegal Taluk, Chamarajanagar District
Kesamudram Mandal, Warangal Dist, Andhra Pradesh
Chinnanagarm Village, Nellikuduri Mandal, Warangal Dist, Andhra
Pradesh
Balugaon Taluk, Kurda District in Orissa
Kulathur Taluk, Pudukkottai District of Tamil Nadu
Kazipet Mandal, Warangal District, Andhra Pradesh
Bolangir Taluk, Bargadh District in Orissa
White Granite quarry at Jalampaly, Vizag Dist. Andhra Pradesh
Marble quarry at Sidhavatam, Kadapa Dist., Andhra Pradesh
Marble quarry at Umpavally, Koraput Dist., Orissa
Yellow Granite quarry at Palghot, Kerala
Yellow Granite quarry at Bolangir, Orissa
Kummam, Karsanur, Tindivanam, Paitur, Atur in Tamil Nadu
Charmarjanagar and Kollelgal in Karnataka and Warrangal in Andhra
Pradesh |
| China |
Shanxi
and Shandong
Hongtang, Tongian, Xiamen |
| Brazil |
Giallo
Veneziano quarry
Nova Venec, Vila Pavao around 145 miles north of Vitoria, the
capital of Espirito Santo
Sta. Cecilia Dourado quarry, located near the village of Vila
Pavao, Espirito Santo
Viana, Espirito Santo |
| Scotland |
Bunessan
, Ross of Mull
Aberdeen, Grampian
St. Andrews, Fife |
| Latin America |
Suriname |
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