Why: Granite and compact sandstone are generally used for buildings situated in industrial towns because they are resistant to industrial pollution and weathering. Marble slab is used for electrical switch boards, slate for roofing purposes, and gneiss is used for heavy engineering works. Compact sandstone has the necessary durability and strength required for industrial environments.

Why: The standard ratio of cement mortar used for stone masonry is 1:3 (cement to sand). This ratio provides adequate strength and workability for binding stones together. Additionally, 15% of cement can be replaced by lime to improve workability and reduce shrinkage. A ratio of 1:3 ensures sufficient binding capacity while maintaining cost-effectiveness compared to richer mixes like 1:1 or 1:2.

Why: Rocks are made up of minerals as their fundamental building blocks. Minerals are natural, inorganic, crystalline solids with definite chemical compositions. Rocks can be monomineralic (composed of a single mineral) or polymineralic (composed of multiple minerals). While crystals are structural forms of minerals and chemical compounds are constituents of minerals, minerals themselves are the primary components that compose rocks used in building materials.

Why: Crushing strength is a critical property for evaluating the suitability of stone for construction. It indicates the maximum compressive stress the stone can bear before failure. A minimum of 100 MPa ensures adequate safety factor for building applications.

Why: Specific gravity is the ratio of the density of stone to the density of water. A minimum specific gravity of 2.7 ensures that the stone is sufficiently dense and has adequate strength for structural applications. Lower specific gravity stones may contain excessive pores and voids, reducing their strength and durability.