Chemical Classification of Rocks // Rock Types // Engineering Geology // Building Material //

Chemical Classification of Rocks
Based on the chemical composition, the rocks are classified as siliceous rocks, argillaceous rocks and calcareous rocks. 
Siliceous rocks 
In siliceous rocks are the sedimentary rocks that have silica as the principal components. 
Generally, these rocks are hard and durable. 

These rocks are also not affected by any external agencies. 
However, silica disintegrates easily in combination with weaker minerals. 
Thus, to be hard and durable these rocks should contain a maximum amount of free silica. 
The examples of siliceous rocks are granites, basalt, sandstone etc. 
Argillaceous Rocks
Argillaceous rocks are those have clay as principal components. 
These rocks are dense, compact and are soft. 
The examples of argillaceous rocks are slates, laterites etc.
Calcareous Rocks
Calcareous rocks are those have calcium carbonate as principal components. 
The durability of these rocks depends on the constituents present in the surrounding environment. 
 The examples of Calcareous rocks are limestone, marbles, dolomite etc.

Video Link: