Physically, they are very Hard, Compact, Fine grained, equi-granular homogeneous rocks of sedimentary nature (Sandstone) & metamorphic nature (Quartzite).
|Color||Minor color tonal variations exist but within the tolerance limit.|
|Hardness||6.5 to 7 on Moh's Scale|
|Density||2.3 to 2.4 Kg/cm3|
|Compressive Strength||90 to 140 N/mm2|
|Modulus of Rupture||16-40 N/mm2|
|Water Absorption||1.0 - 1.2 %|
|Porosity||Low to very low|
Chemically, they are very resistant Mono-Mineralic rocks, principally composed of silica. The other minor constituents vary from origin to origin.
|Alumina (Al2O3)||1 to 1.5%|
|Soda (Na2O) & Potash (Kro)||Less then 1%|
|Lime (CaO)||Less then 0.5%|
|Magnesia (MgO)||Less then 0.5%|
|Loss On Ignition (LOI)||Less then 0.5%|