Characteristic of Good Building Stone

Characteristic of good building Stone

Following are the characteristic of good building stone.

1       Appearance. This property of stone is very impotent for face work of building

 For architectural point of view color of the stone should well and matching with surrounding.

The lighter color stone should be preferred   to dark ones.

Because dark color stone are less durable than the lighter due to the presence of oxide of iron. Due to the presence of oxide of iron there are chances to disfigure the stone with rust stain and to disintegrate it.

2       General Structure. When stone broken in a direction should not give dull in appearance. It should show uniform of texture, crystalline homogenous, close and fine grained. It must be either free from cavity, crack, or pitches of soft are lose material. All the stratification should not be visible with the naked eye except difference in color.

3     Heaviness. Heavier varieties of Stone are very important. It means the stone are more compact, less porous and greater specific gravity. Heaver varieties of stone use in water like Dam, barrages, weirs, docks, harbors,  and retaining walls. The stones used for roof coverings should be heavier one. A stone should have specific gravity between 2.4 - 2.8.

4       Strength. Generally compressive strength is needed. Igneous rock stones are stronger than those of sedimentary rock stone. Usually in construction the stone are use quite strong to stand against the force likely to counter yet. The stone that use in Construction where heavy load and pressure likely to come should tested for its strength.

5       Hardness. Hardness is the Resistance of stone to abrasive force caused by much wear and friction as in pavement, floor, and aprons of bridges and weir, abutment in river.

6       Toughness.  Toughness is the resistance of stone to stand against vibration. This type of stone used at places subject to vibrations, moving and dead loads should be tough.

7       Easy of working. The stone used in making statues (cut, dressed, molded, and carved) like structure should be good enough to be converted into certain shape. Marble is one of the examples but it should be noted that this quality is opposed to strength, hardness  and durability. 

8       Porosity and absorption Exposed surface absorbs rain water which forms acids causing crumbling action. Porous stones are unsuitable for the construction works less porous stones absorb less fluid hence are more durable. In cold climatic regions water may ingress into the pores and freeze in this way the volume of freeze water increase and the result is disintegrate of stone. 

9       Seasoning. All freshly quarried stone have certain amount of moisture known is quarry sap, which is make them soft and easier to work upon them such is dressing, carving and molding. All these work should be done early after quarrying. After querying when has been done upon stone, they should be left for seasoning a period of 6-12 month under the shed having no wall with free circulation of air.

Suitability Stones for Various types of Construction.

S.N.	Type of structure	Type of stone
1	Piers, bridge abutments, light houses, and wires.	Good quality granite, good or stratified granite.
2	Road Pavements and railway ballast	Inferior quality of granite and Gneiss.
3	Road metalling, Paving	Basalt and Trap.
4	Cement concrete	Basalt and Trap.
5	Ornamental work in building	Red and yellow types of basalt and trap.
6	Roof Covering and Flooring	Slate
7	Damp proofing and sills of windows	Slate
8	Partitions in urinals and bath rooms	Slate
9	Monuments, Statues and carved work	Marble
10	Building Construction	Laterite
11	Interior decoration in superior buildings	Serpentine

Cursing Strength (Kg/cm) and Specific Gravity of various types of stones

Stones	Specific gravity	Crushing strength (kg/cm2)
Granite	2.63-2.65	1000-1400
Basalt	3.00	700-850
Sandstone	2.3-2.6	400-650
Limestone	2.3-2.4	400-650
Marble	2.72	500-600
Slate	2.89	750-2100
Quartz	2.65	750