Sandstones

Sandstone in simple terms, is a sedimentary rock composed of small grains of minerals and rocks that are the size of sand particles. These sand like grains are attached together by a binding material that cements the gaps and holds the pieces together. Sandstone is found around the world in sedimentary basins and mined for various construction purposes.

If looked closely, one can easily identify the structure of sandstone as the particles of minerals and rocks that are reduced to the size of sand due to natural weathering, hence the name. Depending on their chemical structure and endurance, the different particles can modify or get destroyed altogether during natural process of locomotion which happens mostly via water. Quartz is the chemical compound that is found in the highest amount in sandstone as it is the most abundant mineral on Earth’s surface and hard as well to endure the weathering during transport.

Types of Sandstone:
While all sandstones are made of the same general minerals, the quantity, structure and chemical equation is what makes them different from each other. The major types of sandstones are:

  • Quartz Sandstone: Quartz sandstone is named after the mineral quartz which is left in high quantity after all the lighter minerals are removed during the long process of weathering. The final step is removal of clay that happens in extreme energy environments. These are light and cloudy due to the high amount of quartz which is naturally clear crystal like in appearance.
  • Arkose Sandstone: Unlike quartz, this type is characterized by high content of feldspar with possible amount of micas as well. Arkose is prepared from the breakdown of granite. These are usually found in dark shades of brown and pink. Arkose sandstones are a common choice for construction purposes and millstones.
  • Lithic Sandstone: Known also by the name of greywacke, lithic sandstone is a composition of all minerals namely, feldspar, quartz, mica with a higher percentage of dark rock fragments which is responsible for their dark color.

Uses of Sandstone:

Sandstone is a popular choice for building stones, decorative purposes and a source for minerals as well.

  • Sandstones are relatively soft as compared to other natural stones, making them easy to carve through hence it is a preferred choice for decoration since ancient times. Garden fountains, accessories, lamps and sculptures are some great options that they can be put to use for.
  • Due to their hard, compact composition, sandstones are also ideal for raising walls. Wall cladding is a popular method amongst stone enthusiasts for their decorative look and strong hold.
  • Sandstone flooring is also a popular application for sandstones for their royal look. Sandstones are naturally prepared with decorative patterns which gives them a rustic appearance making them a preferred choice for flooring. These are also used for pavements in commercial as well as residential establishments.

As it has been established above already, sandstones are dominantly comprised of feldspar, sometimes also silt and clay. The composition of minerals is what determines the color of these stones. These are mostly tan in color due to light minerals. Argillaceous sandstones range from grey to blue; a common shade is that of red which is due to iron oxide (or rust); purple sandstones are also found that is because of high quantity of manganese. India boasts of large variety of sandstones in various colors. Most popular Indian products are Tint Mint, White Mint, Mint Fossils, Modak, Agra Red, Rainbow Sandstone, Raj Green, Teak, Buff Brown, Dhoplur Chocolate, Beige, Dholpur Pink, Lalitpur Pink, Mandana Red, Jodhpur pink, Jodhpur red and Jaisalmer yellow.

Major deposits of sandstone are found in Rajasthan in districts of Bundi, Jaisalmer, Pali, Dholpur, Bharatpur et cetera. Other quarries are located over Southern Eastern states of India. Mostly used as crushed and paving stone, some hardened qualities of sandstones are also used for interior use.