STONES AS A BUILDING MATERIAL

Classification of stones or varieties of stones:-

There are three main classes of rocks. 

CHEMICAL CLASSIFICATION:-

Chemically stones are classified into three groups. which are given below.

• Argillaceous stones:

Argillaceous or clay stones are those stones which contain alumina AL2O3 as principal constituent. These stones are less durable stone. All clay stones belong to this group.

The examples of argillaceous rocks are slate, laterite etc.

• Silicious stones:

The stones which contain silica SiO2 as principal constituent are called silicious stones. These stones are durable stones.

The examples of these type of stones are granite, quartzite and sand stone etc.

• Calcareous stones:

The stones which contain calcareous material CaCO3 as principal constituent are called calcareous stones. They also contain some proportion of siliceous and clay matter.

These type of stones are marble stone and lime stone etc.

PHYSICAL CLASSIFICATION:-

Physically stones are classified as:

• Stratified stones:

The stones which are split into thin slabs or layers easily are called stratified stones. All sedimentary stones are essentially stratified and metamorphic stones may be either stratified or unstratified depending upon its parent stone.

The example of these type of stones are slate, sand stone etc.

• Unstratified stones:

These rocks do not show sign of stratification and can not be easily split into thin slabs or layers are called unstratified stones. All igneous stones are essentially unstratified and metamorphic stones may be either stratified or unstratified.

The example of unstratified stones are granite, basalt and lime trap.

GEOLOGICAL CLASSIFICATION:

Geologically stones are classified into three groups.

• Igneous or primary stones:

These are primary stones which are formed from molten magma. They represent different structural features depending upon the condition of solidification and composition.

Generally igneous stones are strong and durable.

These are also called unstratified stones

The examples of igneous stones are granite, basalt and trap etc.

• Sedimentary or secondary stones:

These are secondary stones and are formed by the denudation and deposition of previously existing stones due to weathering actions.

Water or rain is the most powerful and principal weathering agent. The other destructive agents are frost, wind and chemical actions.The destructive agents break up the surface of earth which gets further broken up when carried down by rains and rivers. When the velocity of water in the rivers carried those broken particles many of them settle down to the river bed and thus sedimentary stones are formed.

These are also called stratified stones

The example of sedimentary stones are lime stone and sand stone.

• Metamorphic or tertiary stones:

Stones which are formed due to metamorphic action of pressure or internal heat or by both alteration of original structure due to heat and excessive pressure are called metamorphic stones.

The example of these stones are Marble.