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 |
| Weather Impact |
Resistant |
Chemically, they are very resistant Mono-Mineralic rocks, principally composed of silica. The other minor constituents vary from origin to origin
| SiO2 |
95-97% |
| Iron (Fe2O3) |
0.5%-1.5% |
| 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% |