Sandstone, as the name spells, is a rock formed of sand or quartz grains tightly pressed together and cemented by variety of materials like silica, iron, lime etc. The grain size, strength, kind of cementing material and compactness determine its density, permeability and the use. The colour of sandstone depends on cementing materials viz. ferruginous sandstone are red to brown, argillaceous are earthy to buff and generally white. Due to oxidation the ferruginous sandstone generally tend to change the colour from radish to brown buff, yellow and greenish.
Among dimension stones sandstone has a significant status for its availability and durability and grand spectrum of colours with universal appeal that even rainbow spectrum fails to match.
For centuries sandstone is being used, not only in India but all over the world, for different purposes. The wide scale architectural application of sandstone can be seen in different monuments, temples and buildings in India: Red Fort of Delhi and Agra; palaces and buildings of Fatehpur Sikri, Deeg, Kota, Bikaner, Jodhpur and Jaiselmer; Buddhist Rameshwaram temple in the south; Parliament House, Presidential House, Supreme Court building and Swaminarayan Temple in Delhi, Mehrangarh Fort and Umaid Bhawan Palace at Jodhpur and Rajasthan Assembly House in Jaipur.
Rajasthan is the treasure trove of sandstone, more than ninety per cent share of Indian sandstone deposits are found here. In the last decade sandstone quarrying, processing and marketing in Rajasthan have achieved a remarkable growth showing good future prospects.
Sandstone reserves in India are estimated at around 1,000 million tonnes and spread over in the states of Andhra Pradesh, Assam, Bihar, Gujarat, Haryana, Madhya Pradesh, Meghalaya, Mizoram, Karnataka, Orrisa, Punjab, Rajasthan, Uttar Pradesh, Tamil Nadu and West Bengal. Out of 1,000 million tonnes of sandstone in India, 900 million tonnes are in Rajasthan spread over in the districts of Bharatpur, Dholpur, Kota, Jodhpur, Sawai Madhopur, Bundi, Chittorgarh, Bikaner, Jhalawar, Pali and Jaisalmer.
Geologically sandstone rocks of Vindhyan Supergroup extending from Chittorgarh (Rajasthan) in the west to Sasaram (Bihar) in the east, Harda to Hoshangabad (Madhya Pradesh) are most significant. The other rock units correlated with Vidhyans are Kurnool System in Kundair Valley and Paland Tract in Andhra Pradesh, Indravati and Raipur series in Baster and Chhatisgarh area, Bhima series in Gulbarga and Bijapur districts of Karnataka.
The Gondwana sandstones found in Bihar and Orissa have been widely used as building stone in the states. The famous Lord Jagnnath Temple at Puri and other temples at Bhubneshwar as well as sculptures in nearby caves at Khondagiri and Udayagiri have been built with the Gondwana sandstone called Athgarh Sandstone.
Sandstone of Cretaceous age, popularly known as Himmat Nagar Sandstone, Dhrangdhara Sandstone and Songir Sandstone of Gujarat ; Nimar Sandstone of Narmada Valley have been widely used in building work.
The sandstone occurring along the eastern coast (Cuddalore and Rajamahendry in Tamil Nadu and Andhra Pradesh) have been used as building material. The famous Rameshwaram Temple has been built from Cuddalore Sandstone.
Geologically Rajasthan is the largest sandstone producing state of India where sedimentary formations are exposed in its 17 districts, covering an area of about 34,000 sq m. Large deposits of splittable sandstone are confimed in an area of 16,000 sq km out of which 10,000 km lies in eastern and south-eastern Rajasthan covering districts of Dholpur, Bharatpur, Karauli, Sawai Madhopur, Bundi, Kota, Jhalawar, Baran, Bhilwara and Chittorgarh.
The scattered sandstone exposures of western Rajasthan are confined to Jodhpur, Nagaur, Churu, Bikaner and Jaisalmer districts covering about 6,000 sq km area.
The sandstone producing districts in Rajasthan have been divided into different groups to form different mining clusters. Each cluster is producing sandstone with certain distinguishing features.
Covering Kota, Jhalawar and Baran districts (120 sq km) the cluster produces fine grained, hard, compact and different colour sandstone, which includes white to buff, pale grey, red, cream, brown and spotted brown.
Bundi - Bhilwara - Chittorgarh Cluster
This area produces sandstone of medium to fine grained in purple, redish brown with pale white bends and is compact, massive and having quardrangular joints.
Dholpur - Bharatpur - Karauli - Sawai Madhopur Cluster
This cluster cover 25,000 sq km area. The sandstone from the cluster is extensively quarried in Sar-Mathura, Bari, Baseri, Hindaun, Sapotra, Masalpur, Rupwas, Bund Baratha and Bansi Paharpur areas. Red, pink and cream colour sandstone are the main varieties produced in these areas. The sandstone from these areas are comparatively soft and most suitable for stone craft purpose. Its extensive use can be seen at Red Fort of Delhi and Agra, Parliament House, Supreme Court and Swaminarayan Temple at Delhi and Rajasthan Assembly building at Jaipur.
Jodhpur - Nagaur Cluster
The cluster comprised of Jodhpur, Bilara and Nagaur regions is spread in 6,000 sq km. The sandstone produced at these areas is coarse to medium grained in red, buff, beige, pink and white colour.
The sandstone occurring in the vicinity of Jodhpur is popularly known as Jodhpur sandstone, which has been quarried and used for centuries in buildings, forts, palaces and monuments. Among the most remarkable construction displaying massive use of Jodhpur sandstone, Mehrangarh Fort, Jaswant Thada and Umaid Bhawan Palace are the best examples.
It is because of the strength, resistance to abrasion and aesthetic look of Jodhpur sandstone that more and more professionals from the building and construction field are taking fancy to it. Today Jodhpur sandstone is exported to Sharjah, Dubai, Korea, Singapore and USA in processed form. Workable and good quality sandstone is found in over 150 sq km area round Jodhpur.
The sandstone found in the cluster is located at Jaisalmer town, Bada Bagh, Hamira, Bedasar, Habur, Mokal and at some other places. This cluster is yet to be developed to utilise its full potential.
In general the sandstones of Rajasthan are fine grained, compact and can be easily dressed, chiselled and take good polish. These can also be sawn and cut to size. These are available in different names:
Rajpura Green, Rajpura Pink, Khatu Teak, Khatu Rainbow, Budhpura Grey, Kandla Grey, Bhilwara Brown, Dholpur Beige, Dholpur Red, Dholpur Pink, Chocolate, Bansi Pink, Mandana, Chittar of Jodhpur, Tera Red etc.
Rajasthan sandstone industry has evolved into the following production and manufacturing categories:
- Blocks for monumental and building purposes
- Processed stone for monuments and tombs
- Sculpture and artefacts
- Structural slabs
- Calibrated modular tiles
- Cobbles, cubes, Kerbs and landscape garden stone
One sector where sandstone is widely used is handicrafts sector. Most of the stone handicrafts manufacturing units are cottage industries. The number of such units is over 1,000.
The physico-mechanical and chemical properties of sandstone quarried from different areas in Rajasthan determine its quality, colour and use.
Looking to the massive use of sandstone in rapidly growing building and construction industry in India and the increased demand of the material in foreign countries a Stone Park has been established near Jodhpur city with the help of Rajasthan State Industrial Development & Investment Corporation Limited.
Though Rajasthan is providing sandstone in different colours and finishes meeting maximum demand at domestic as well as foreign level, there are other states too in India producing sandstone.
This state is producing some specific type of sandstones.
Sagar Black Sandstone
This is a black sandstone rarely available anywhere outside India. Its physical and chemical properties make it a preferred option for all type of construction activities. Available in attractive shades, this stone is considered ideal for wall cladding, flooring, garden furniture, handicraft etc.
Sagar Black Sandstone has high compressive and flexural strength with negligible porosity, low water absorption and high resistance to weathering etc. It is suitable in industrial and residential constructions and is available in different finishes like hand cut, machine cut , one side and both side honed, polished mirror finish, calibrated etc. Sagar Black Sandstone tiles are available in different sizes and thicknesses. The material is also available in the form of slabs, bricks, steps, cobbles and pebbles.
This stone is having unique fern like fossil shapes on them which are formed by mineral deposits on these stones, which helps in adding a distinctive touch to its appearance. The stone is available in different sizes in thicknesses of 10 - 20mm and 25 - 40 mm and in various finishes: hand cut, machine cut, one side and both sides honed, polished, mirror finish, calibrated etc.
Gwalior Mint Sandstone
It is of greenish white colour. Minor colour tonal variations exist but within the tolerance limit. Gwalior Mint is suitable for flooring, wall cladding due to its physical and chemical properties. It has very smooth natural split surface. It is also suitable for carving and making stone handicrafts.
Gwalior Mint Sandstone is available in cut-to- size, slabs and tiles, and in various finishes like natural cleft, honed, polished, flamed etc. The superior finishing does not require much maintenance. It is available in different sizes in thicknesses of 10 - 20 mm and 25 - 40 mm as natural cleft tiles.
Lalitpur Yellow is extracted in Lalitpur, Uttar Pradesh. It is specially useful for exterior cladding in sea shore buildings due to acid & thermal properties. As such the effect of saline winds is negligible on Lalitpur Sandstone. The gold yellow hue of this sandstone makes it popular with architects and builders.
The stone is available as blocks, slabs, tiles and cobbles in different surface finishes, and in different sizes with thickness of 15 - 50mm and 18 - 22 mm.
Indian Sandstone is a well established material in domestic as well as international market. Today it is because of revolution in stone quarrying and processing technology as well as development in transportation and information technology that Indian sandstone industry has found a niche in the international market. The finished and semi-finished material is exported to various countries. Of course Rajasthan, being the hub of quarrying, processing and trading of sandstone and the products thereof, in exporting different varieties of sandstone products to USA, UK, Middle East Countries, Australia and New Zealand and to some Asian and European countries sharing maximum of the total export.
Apart from its modern applications in Swaminarayan Temple built in the recent past in Chicago - USA, Neasden - UK, New Delhi and Jaipur in India and in some other important constructions such as Biogen Idec Pharmaceutical campus in San Diego, USA. Indian Sandstone presents an impressive reference point of its historical applications at the Jagganath Temple at Puri in Orrissa and Rameshwaram Temple in Tamil Nadu.
Owing to its strength, durability, resistance to abrasion and environmental weathering, acid and alkali resistance and advantage of easy handling and availability has made Indian Sandstone the material of choice for construction and making artefacts and decorative items. It has variety of applications in roofing, flooring, paving, panelling, beams, pillars, doors and window sills. It has been found most suitable for carving screens. It is most suitable for use in chemical factories.
Indian Sandstone is available in various finishes such as natural cleft, flamed, polished, honed, bush hammered, sawn, acid washed, antique finish and sand blasted to suit different applications. The finish and smoothness of tiles and slabs of sandstone depends on the finish of edges, which is available in machine cut, sawn, hand chiseled, hand dressed and chamfered, beveled. The edges play a major role in the overall appearance of the architecture they are used in .
Though sandstone is durable and long-lasting material, a little care will enhance its life while maintaining the original beauty and charm for many generations to come.
Sandstone can be cleaned effectively and safely with warm water or with a clean non-treated dry dust mop. Scouring powders or creams should not be used for cleaning. Trivet or mats must be used before placing hot pans on sandstone slabs or tiles