After shale, sandstone is the second most common sedimentary rock on the Earth’s crust. Due to the abundance, diversity in texture and mineralogy, sandstones are important indicators in some erosional and depositional processes. Also owing to many physical properties that sandstone has, the sandstone slab and tiles are used in many architectural and constructional projects for different purposes. Here in this article our focus is to find answer to the question of “what is sandstone made of?”.
Sandstone Features
Sandstones are silicate based sedimentary rocks. They are consisting out of a great amount of sand-size grains. These grains can bond and blend together in two different ways. The first process can happen by presence of interstitial chemical cement or in another way they can be lithified into a cohesive rock under the pressure and compaction of the sand-size components together with finer-grained matrix components.
Sandstone properties
Sandstones are remarkable natural rocks for many reasons. One of which can be its availability all over the world. Researches and records have shown that sandstone presents 10 to 20 percent of Earth’s sedimentary rocks. These amazing natural rocks can have great resistant facing erosion, so they can last long and exist in various landscapes with different conditions.
Folded and flat-lied sandstones
When the sandstones are folded, they will create backbones of mountain ranges. For instance, the Appalachians of eastern North America, the Carpathians of east-central Europe, the Pennines of northern England, and the Apennine Range of Italy are all made out of folded sandstones. If the sandstone is just flat-lied, they form broad plains and plateaus such as the Colorado and Allegheny plateaus. These can result in different quarries and therefore various types of sandstone slab and tiles.
Sandstone components
Many people assume that sandstone is a rock that has only made out of sandy minerals. in below we will give you more details and information about sandstone components. Sandstones are made out of three basic components. having information about this components also help you to make your own sandstone easier.
Detrital grains
The detrital grains are the most important components; without them the sandstone won’t be shaped. They basically are sand-size minerals like quartz and feldspar, that are transported in various ways to different places.
A cement
A cement has the most important job in making sandstones. Cements act just like a glue and keep all the sandy-grains together which shapes the sandstones. These chemically precipitated in crystalline form from solution; not only they keep the grains together but also fill up the original pore and empty spaces between the grains which can result in the durability of the stone.
A detrital matrix of clay or mud
the clay or mud detrital are not very essential for all types of sandstones. for example, they are absent in formation process of the “clean sandstones”.
Formation process of sandstone
Sandstones have always been available or in the process of shaping in all geologic ages. The natural formation process of sandstone takes time and has two main or principal stages:
Stage one
Firstly, the grains transported with water -in various ways such as in a river, lake, or sea – or from air as for desert locations must be placed in a certain location. one or several layers of sandy grains should accumulate and make the sedimentation.
Most of the time the sedimentation process happens by the suspension of the sandy grains; the grains are stopped after they are rolled or bounced along the bottom of the sea or a river -a body of water- or on a ground surface for desert locations and sand dune regions.
Stage two
When the grains have finally accumulated, they will be compacted under the pressure caused by all the overlying deposits. Then with a cement made out of precipitation of minerals, the empty spaces between grains are filled and they are glued together.
Silica and calcium carbonate are two of the most known and common cementing materials and often, they are obtained from dissolution or out of various alterations that the sand has gone through after it was buried.
In another words, sandstone is basically formed from the sand of older, fragmented or smashed rocks. If you think about it, it takes so many of these tiny grains just to have one block of sandstone. When the grains bond and compressed together, form sandstone blocks.
even though that the sand grains are the most common component in the sandstone, other materials can be found in it like cement and matrix. Usually the cement that exists within the stone is made out of quartz, calcium carbonate or iron oxide. If the sandstone has too much cement materials, it is known to be a poorly formed sandstone.
As we mentioned earlier, when the conditions that we listed above exist, sandstone can be made and seen in almost any location. just note that most of the times, the formation process of sandstone occurs in water body sites like rivers, lakes, the ocean floors or with air in desert dunes.
Sandstone colors
Sandstones are available in various color pallets. Based on the detrital grains and bonding materials the color of sandstones can change and be different. For instance, the pink colored sandstones have great amount of potassium feldspar in them or if Iron oxide cement are available in the formation process, they can impart various tones of yellow, orange, brown, or red. As for the presence of calcite, the sandstone will turn out to be in a gray color tone. If the sandstone is glassy and white, it must almost be only consisting quartz grains.
And lastly, the chloritic clay matrix’s can result in a greenish black color sandstone with extreme hardness.
Classification of sandstones
There are various ways and systems for categorizing of sandstones. For example, the most common and famous system that geologists use is based on both texture and mineralogy of sandstones.
Sandstones are all generally made out of same minerals, but based on the detrital grains and bonding materials they can get different properties which results in sandstones having different classifications. Due to the presence of various components, sandstones are available in diverse colors, tones, shades, textures and grains.
Sandstone classification based on color and hardness
Based on hardness and color, sandstone is categorized in four different groups:
- Gray sandstone
- Crystallized sandstone
- Hard sandstone
- Carbonate cemented sandstone
Gray sandstone
just as it obvious in its name, the grey sandstone is formed from mixture of several shades of grey grains. in comparison to other kinds of sandstone, the durability and hardness of grey sandstone is not much especially on the edges. Which can mean that the edges can shatter under minor impacts or pressure. By knowing that fact, the grey sandstone shouldn’t be used for applications in which there can be high foot traffic or great amount of loads on them. For instance, it is not advised to use grey sandstone for paving your driveways.
Crystallized sandstone
The crystallized sandstone has a white color with a sugary texture and appearance. In comparison to grey sandstone, crystallized sandstone is more durable but they can be fragile and brittle to. If you want to use a sandstone that can add luxurious look and elegance to your place, the crystallized sandstones won’t disappoint you with their polished and smoothed surfaces.
Hard sandstone
The hard sandstone category has some properties of grey sandstone and some of crystallized sandstone; which means its color is similar to grey sandstone but its characteristic features in more like the crystallized sandstone group. The hard sandstones have hard but fragile textures.
Carbonate cemented sandstone
Carbonate cemented sandstones are the rarest and unique kinds of sandstones to find. They can be seen as a type of gray sandstone in which its grains are glued together with either iron carbonate or calcium carbonate cement. These cements will make the main part of the rock hard which can also leave a brown or yellowish stain around the stones core. If you want to recognize which cement is used know that the calcium carbonate cement will make a sandstone with a bubbly texture; but if the stone is made by iron carbonate cement, it should have deep brown stains with a sugary appearance its broken edges.
Sandstone classification based on its compositions
This classification is another geological method. Based on the variation in composition and cementing materials in sandstone formation process, there are three different categories with can also indicate the depositional history, including:
Quartz Sandstone:
Quartz sandstone are suggested to have taken a very long time for their depositional process.
Arkose:
The Arkose sandstones are mainly made out of feldspar which can weather quickly and cause sandstones to have pink colors. This means that unlike Quartz sandstone, Arkose rocks take a short period of time for their depositional process.
Litharenite or lithic sandstone:
all the sandstones are resistant to erosion but this category and type of sandstones, specifically indicate that they have been shaped in an arid environment or with an accelerated erosion.
Here at Unikastone, we have various sandstone slab and tiles that you can choose them for different applications. Note that most of our sandstone products are directly imported from India the country that provides the best quality sandstones all over the world. Our aim is to please and help our customers. For more information, contact us. we will be more than happy to help.
what are gray sandstone features?
just as it obvious in its name, the grey sandstone is formed from mixture of several shades of grey grains. in comparison to other kinds of sandstone, the durability and hardness of grey sandstone is not much especially on the edges. Which can mean that the edges can shatter under minor impacts or pressure. By knowing that fact, the grey sandstone shouldn’t be used for applications in which there can be high foot traffic or great amount of loads on them. For instance, it is not advised to use grey sandstone for paving your driveways.
what are sandstone component?
- Detrital grains
- A cement
- A detrital matrix of clay or mud
