• Granite is a common variety of igneous rocks.
• It is hard, tough and is found in variety of
• It is used as large building blocks for heavy
engineering works such as piers, abutments
of bridges, etc.
• It is used or constructing steps, sills and
6. BASALT AND TRAP
• These are hard and tough and are greenish
grey to dark grey in color.
• They are more suitable as road metal, railway
ballast and as an aggregate in concrete.
• They are also used as flag stones for paving
streets and for constructing steps.
• Sandstone is a common variety of
• Its compact and fine grained variety is used in
ashlars masonry and other works of
• It is also used in heavy engineering works
such as monumental buildings, dams, docks,
• Limestone are the common variety of
• These are unsuited for external work in
• It is used in masonry walls and paving streets.
• Slate is a common variety of metamorphic
• It is hard, tough and least absorptive and
gives ringing sound when struck with a light
• Being absorbent it is also used in bath,
cisterns, urinal partitions, etc.
• Marble is compact and crystalline in structure
due to which it takes a fine polish.
• It is less durable and its absorption is 1 to 3%.
• It is mainly used for ornamental and highly
specialized building works as in columns,
staircases, table slabs, window sill, floor
finishing, steps, etc.