The characteristics of good building stones

 Stone is a naturally available building material, which has been form the early age of civilization.  It is available in from in the form of rock, which is cut to the required size and shape and used as building block. Stone has been used to build small residential building to large places and temples.

Stones should possess fine – grained texture. It should be free from soft patches, flows and cracks

The strength of stone should be ascertained if it is to be subjected to any excessive or unusual stresses.

Shade of the stone should be uniform and pleasing.  Freshly broken surface should be bright and cracks

The stone should be strong, hard and durable. the hardness of stone is often of importance, especially if it is to be subjected to a considerable amount of wear and friction, as in pavements. 

The specific gravity should not be less than 2.5

It should possess good resistance to weathering

It should be easily workable before seasoning.the appearance of stone is often a matter of importance, especially in the face work of conspicuous buildings.In order that the appearance may be preserved, a good weathering stone should of course be selected, free from flaws, clayholes, etc.

It should have good resistance to smoke, fire and acidic atmosphere

It  should not absorb more than 5% of water by weight, when kept immersed in water for 24 hrs.

In attrition test, the stone should not show wear of more 2%

The weight of a stone for building has occasionally to be considered. In marine engineering works it is often advisable to use heavy stones to resist the force of the sea. A light stone would be best adapted for arches, while heavy stones would add to the stability of retaining walls.

It should become hard after seasoning. This seasoning gets rid of the moisture, sometimes called "quarry sap," which is to be found in all stone when freshly quarried.

Toughness index should be more than 19