Building stones are obtained from rocks occurring in nature. It is estimated that the three-fourth of the land area of the globe is underlain by sedimentary rocks and the remaining one-fourth by igneous and metamorphic rocks.

The various types of rocks derived from these types of rocks are as follows,

1. Principal stones from igneous rocks. i.e., Granite, Basalt, Trap.

2. Principal stones from sedimentary rocks. i.e., Sand stone, Shale, Lime stone and Laterite.

3. Principal stones from metamorphic rocks. i.e., Quartzite, Schist, Slate, Marble and Gneiss.

Requirements of a good building stone:

A good building stone should possess several characteristics such as high strength (i.e., crushing strength > 1000 kg/cm2), high durability, sufficient hardness (i.e., coefficient of hardness > 14), high resistance to wear, good fire resistance, specific gravity more than 2.7, crystalline structure, high impact value (i.e., toughness index > 13), low water absorption (i.e., Percentage absorption after 24 hours less than 0.6), facility for carving and dressing, weather resistance and better appearance. Generally stones from igneous and metamorphic rocks are heavier and more durable than stones from sedimentary rocks.

Uses of Building Stones

1. It is very hard and durable suitable for works of importance such as bridge abutments, piers, etc.,
2. It is also used in foundation structures also,
3. It is used in random rubble masonry,
4. It is suitable for ornamental and superior type of building work.
5. It is also suitable for flooring and veneer work.