Correct Answer - Option 2 : 2.5 to 3.0
Concept:
A good building stone has the following properties:
- The percentage of wear in the attrition test should not be more than 3
-
Specific gravity for most of the building stones lies between 2.5 to 3. Mostly specific gravity should be taken at least 2.7
- The coefficient of hardness should be greater than 17
- Percentage of water absorption by weight of stone should be less than 5
- The toughness index should not be less than 13
- Crushing strength should be greater than 100 N/mm2