Stone:

A construction material derived from rocks in the earth’s crust and mixture of two or more minerals is called stone.
Stone is a ‘naturally available building material’ which has been used from the early age of civilization. It is available in the form of rocks, which is cut to required size and shape and used as building block. It has been used to construct small residential buildings to large palaces and temples all over the world. Red Fort, Taj Mahal, Vidhan Sabha at Bangalore and several places of medieval age all over India are the famous stone buildings.
Building Stones
Stone as building material lost its importance due to

Advent of cement and steel
Structural strength can not be rationally (wisely) analyzed
Transportation difficulties
Dressing problems

Classification of Rocks:

Geological classification

Igneous rocks (primary, un-stratified, eruptive) – cooled down molten volcanic lava (magma). Basalts and granites.
Sedimentary rocks (aqueous, stratified) – gradually deposited disintegrated rocks. Sand stones and lime stones.
Metamorphic rocks – transformed due to great heat and pressure. Granite to gneiss, lime stone to marble, shale to slate.

2. Physical classification

Stratified rocks – separable distinct layers. Cleavage plane of split visible. Slate, sandstone, lime stone.
Un-stratified rocks – no sign of strata, cannot be easily split into slabs. Granite, basalt, trap.
Foliated rocks – having tendency to split up only in a definite direction.

3. Chemical Classification

Siliceous rocks – containing silica SiO2 (sand) and silicates. Granite, basalt, trap, quartzite, gneiss, syenite, etc.
Argillaceous rocks – containing clay or alumina Al2O3. Slate, laterite, etc.
Calcareous rocks – containing calcium carbonate or lime. Limestone, marble, dolomite, etc.

4. Practical Classification