Qualities of a Good Building Stones

 The following are  the qualities or requirements of a good building stone. 

1. Crushing strength:  For a  good  building stone,  the crushing strength should be greater than l000kg per cm2. 

2. Appearance:  Good building stone should  be  a uniform colour,  and  free from  clay  holes, spots of other  colour bands etc  capable  of preserving the  colour  for longtime. 

3. Durability: A  good building stone  should  be  durable. The factors  like  heat and cold alternative  wet  and dry,  dissolved gases  in rain, high  wind  velocity  etc  affect  the durability. 

4. Fracture: For good  building  stone its fracture should  be sharp,  even and clear. 

5. Hardness:  The hardness  greater than  17, treated  as  hard used in  road works. It is between 14 to 17,  medium hardness, less 14 said be  poor hardness. 

6. Percentage wear:  For a  good building stone, the percentage wear should  be  equal to  or  less then  3 percent. 

7. Resistance to  fire: A  good  building  stone be  fire proof. Sandstone,  Argillaceous  stone resists fire quite  well 

8. Specific  gravity: For  a good building stone the  specific gravity  should be greater then  8.7 or  so. 

9. Texture:  A  good building stone  should  have  compact fine crystalline  structure should be  free  from  cavities, cracks  or patches of stuff or loose material. 

10. Water absorption:  For  a good building stone, the percentage absorption by  weight  after 24 hours should not  exceed 0.60. 

11. Seasoning:  Stones  should be well  seasoned before putting into  use. A period of  about  6 to  12  months is considered  to be sufficient for proper  seasoning. 

12. Toughness Index:  Impact  test, the  value  of toughness  less than  13 – Not tough,  between 13 and   19 –  Moderate,   greater than  19- high