Granite

Property

Group

Igneous

Common Rock-Forming Mineral Group

Siliceous

Composition

Feldspar, quartz, and small amounts mica are the primary minerals of the average granite with minor accessory minerals.

Hardness

Hard

Porosity %

0.4 – 2.3 [6]

Density

2.5-2.7 g/cm³ [6]

Abrasion Resistance

0.68-4.1 mm

Compressive Strength

107.56 – 212.37 MN/ m² [7]

Modulus Rapture

10.27 – 21.10 MN/ m² [7]

Mohs’ Scale

5 – 7

Absorption %

0.05 – 0.5

Coefficient of Linear Expansion

3.7 – -6.0 /ºC -1 x 10⁶ [6]

Specific Gravity

2.61-2.70 kg/m³ [7]

Weight

2611.26-2707.38 kg/m³ [7]

Weathering Characteristics

Generally good to excellent. However, like any other material it has its vulnerable points

Some varieties contain ferrous mineral compounds that when continuously exposed to moisture, will undergo mineralogical changes and being to produce discoloration (rust spots) i.e. Rustic Yellow.

Tendencies

Absorbs oils and some will absorb other liquids

Generally not affected by acidic foods and drinks, however, polished granites can be etched by hydrofluoric acid and concentrated acids which are found in some household cleaning products

Some granite varieties when used in water features (spas and fountains); will begin to show signs of deterioration in a few years.

Acid Resistance

Acid gases such as sulphur dioxide attack stones containing carbonate material such as calcite and dolomite. This may leads to either erosion causing surface loss or crystallization damages.

Durability Test

Test typically includes salt crystallisation, acid immersion, thermal shock, resistance to ageing by humidity, temperature, SO₂ action, and resistance to ageing by salt mist.

Colors

Granite is found in more than a hundred distinct colors with varying patterns.

Finishes

• Polished
• Honed
• Flamed
• Bush Hammer

Thickness

10-15 mm for internal wall; up to 20mm for floor.

ASTM C 615 Physical requirement

* Abrasive hardness values