Granite is an igneous rock composed of feldspar, mica, and silica that comes in various colors like gray and red. Medium-grained granite is well-suited for construction while fine-grained granite can be polished but is harder to work. Sandstone is a sedimentary rock consisting of fragments cemented together, and it comes in colors like white, yellow, and brown. Marble is a metamorphic rock formed from limestone that is easy to carve and comes in colors such as white, black, and green.
12.
Granite is an igneous rock, ordinarily composed of feldspar, mica,
and silica or quartz.
Qualities of Granite
The hardest and most durable granites contain a greater proportion of
quartz and a smaller proportion of feldspar and mica.
Granite has a pearly lustre. The colour of common granite varies from
white through yellow to deep red, and the stone is generally classified
as gray and red.
Medium grained stone is best fitted for building construction.
Fine grained stone can be carved and polished, but, on account of its
extreme hardness, it cannot be worked readily.
14. Sandstone
A Type of Sedimentary rock
Sandstone consists of fragments of other rocks cemented
together. The cementing material may be silica, oxide of iron, clay,
or carbonate of lime.
Qualities of sandstone
The best stone is characterized by small grains with a small
proportion of cementing
material. When broken, it has a bright, clear, sharp fracture.
The colours of sandstone are white, cream, yellow, dark brown,
blue, and red
Technical Information of different Sandstones
15. Metamorphic Rocks
Marble
Metamorphosed limestone gives the masonry material known as
marble. It is easily dressed to a smooth surface and polished, and is
considered one of the most valuable building materials.
Qualities of marble
Marble can be obtained in many colours, some of which are white,
gray, red, blue, green, and black.
It is easy to carve; the finer the grains of the stone, the more
suitable it is for this purpose.
It resists frost and moisture well, but like all limestones it does not
withstand fire.
Classification
Marble has been classified into 10 groups by Bureau of Indian
Standards (IS 11301969) on the basis of colour, shade and pattern.
1. Plain White Marble 2. Panther Marble
3. White Veined Marble 4. Plain Black Marble
5. Black Zebra Marble 6. Green Marble
7. Pink Adanga Marble 8. Pink Marble
9. Grey Marble 10. Brown Marble
17. 1. Dressing of stones is tedious, laborious and time
consuming job.
2. Desired strength and quality not available at
moderate rates especially in plain areas.
3. RCC, Steel are alternatives to stones and gives
more strength and flexibility.
4. Stone structure design can’t give freeness and
flexibility to the designer.