Granite

Granite

Granite Physical Properties

Granite rocks are igneous rocks, formed by slowly cooling pockets of magma that were trapped beneath the earth's surface. Physically, commercial granites are hard, compact rocks with fine to coarse grains of metamorphic or igneous origin. In terms of properties granite is a unique material. The properties lending uniqueness to granite are:
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
The other properties of Granite are:
Porosity/permeability
This hard rock has almost negligible porosity ranging between 0.2 to 4%.Thermal Stability
Granite is highly thermal stability and is impervious to weathering from temperature. Even air borne chemicals have no effect on it. It is highly resistant to chemical erosion making granite useful for making tanks to store highly caustic material.

Co-efficient of expansion
The co-efficient of expansion for granite varies from 4.7x10-6 – 9.0x10-6(inch x inch).

Variegation
Granite has high consistency in color and texture.

Hardness
Hardness of granite lends it excellent wear, making it excellent building stone.

 

Chemical Composition

The chemical composition of granite, by weight percent:
SiO2-72.04% (70-75%)
Al2O3-14.42% (10-15%)
K2O-4.12% (4-6%)
Na2O-3.69%
CaO-1.82% (0.5 - 2%)
FeO-1.68% (1.5 - 3%)
Fe2O3-1.22% (1 - 2%)
MgO-0.71% (0.5 - 2%)
TiO2-0.30% (0.2-0.5%)
P2O5-0.12%
MnO-0.05%

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