Marbles have sufficient strength to beam building loads and at same time can be given any desirable shape because of ir low hardness. Marble can take a brilliant polish.

Igneous rocks being crystalline in character, compact and interlocking in texture and uniform in structure possess very high compressive strengths compared to sedimentary and metamorphic rocks.

Bulk density is density of rock with natural moisture content. It is assumed that in such cases all pore spaces are not filled with water.

Many orwise sound building stones like granites and or coarse grained igneous rocks are poor in fire resistance. These may become unsuitable for use in heat intensive situations.

The load at failure divided by area of cross-section of sample gives unconfined compressive strength of rock. The value is termed unconfined or uniaxial because test specimen has no lateral support or restraint and is being compressed only along one axis.

Common bitumen is generally anionic in character. Any aggregate having electrolytic property will behave as hydrophobic or water repelling and vice-versa. This holds well in aggregates.

The tensile strength of rock samples may be determined directly or indirectly. The direct method would require elaborate means to avoid bending while applying tensile forces. Hence usually indirect methods are used to find out tensile strength of stones.

Following are most important properties a good road stone should possess- sufficient hardness and toughness; durability at place of use; cementation capacity; non-swelling or hydrophobic property.

Numerically, porosity is expressed as ratio between total volume of pore spaces and total volume of rock sample and is expressed commonly in percentage terms.

Granites show very high crushing strength, low absorption value, least porosity, interlocking texture, variety of appealing colours and capacity to get brilliant polish.