Natural materials

Natural materials – clay

In this blogpost we will explore one of the most common natural materials in the world, clay.

What is clay?

Clay is a natural fine-grained material which smoothens out easily under pressure and is often filled with water.

The composition of clay is typically filled with minerals such as kaolinite, etc. these minerals are important for the beauty industry as most common type beauty products utilize some form of clay minerals. Additionally clay minerals are important in certain types of pharmaceutical industries as binders, lubricants, diluents, pigments and opacifiers.

History of clay in pharmacy

The use of clay in the pharmaceutical industry dates back to prehistorian eras where it has been used in pottery for containers of medicine and in 1600 BC a ‘book’ containing evidence that clay was used against hemorrhages and other types of diseases has been found. Underlining the fact that clay is a crucial part of human society for thousands of years.!

Another prehistorian example of clay as a pharmaceutical instrument is In the 400’s BC a book by Hippocrates called “On Airs, Waters and Places”. In this book they describe the Armenian bole and clays usage in healing dysentery and diarrhea. The Armenian bole is a special type of clay often used as medicine, as a pigment and gliding material. It is often red due to the presence of iron oxide.

The important compounds of clay in pharmacy is their mineral composition. In order to characterize clay it usually is subdivided into four main groups corresponding to the mineral content. These are:

  • Kaolinite
  • Smecticte
  • Illite
  • Chlorite

Where further subdivisions can be made of clay based on the mineral plate layering as outlined in Table 1.

S. No.General FormulaGroupLayer Type
3Montmorillonate (Al1.67Mg0.33)
Si4O10(OH)2M + 0.33
Saponite:Mg3(Si3.67Al0.33)O10(OH)2M + 0.33
Palygoskite-sepiolite group
Table 1: Mineral compounds typically found in clay with subdivisions based on typical geometries and mineral composition.

Common use cases of clay

The usages of clay are plentiful and it has been used for various amounts of pottery throughout history. These types of pottery have played an important role when trying to establish a culture and society, as containers have been produced holding everything from water to spices.

In modern history after the industrialization it has been possible to mass produce pottery instead of individual people being employed full time with the occupation suddenly it was possible to free up time for individuals now focusing on something more productive such as innovation and rethinking new technologies.

Related read: Natural Materials – Sand, Common misconceptions of Tsunamis.

Clay pottery as food storage

Meanwhile clay pottery is still used today to store all kinds of inventory such as food, spices and vegetables. With the advent of vegetarianism it might be reasonable to ask: Is clay vegan friendly? And to that the answer is a sounding yes! Clay is absolutely vegan friendly as the compounds making up clay pottery is entirely from non-animal origins meaning that anything vegan that you put in a clay bowl or pottery stays vegan.

Additionally clay pottery is able to withstand high temperatures and doesn’t decompose easily when burnt. Furthermore the trash from clay pottery is entirely natural and thus no need to worry about environmental hazards from trashed clay pottery.

Clay as a building material

Another usage of clays is as a building material for bricks, huts and similar. Here the clay is used to mold bricks in huge ovens allowing for hardening. When hardened and burned, the resulting bricks are capable of withstanding outside weather, rain and storms.

Clay bricks for building have been used for millennia and such the technology of creating bricks from ‘mud’ is something that has withstood the test of time. In a primitive manner, the recipe for creating clay bricks is simple; Mix water, clay, straw and heat until hardened in high temperatures.

Creating bricks with bare hands

An excellent resource for showcasing the simplicity and ancient technology associated with the clay brick creation is the Youtube channel ‘Primitive Technology’. A guy shows in simple steps how to create clay bricks from raw materials.

Video 1: Fired clay bricks as a primitive technology for brick creation

This way of creating bricks is simple yet effective and can be understood through the use of ancient technology.

The flow of liquids through clay

Unlike other materials such as sand, clay has quite an adherence to water. it is hydrophilic in the sense that most clays adsorb water in huge amounts leading to saturated soils. Additionally water passes extremely slowly through clay meaning that it acts as plug stopping all of the water trying to go through.

This property of plugging water and other liquid substances from flowing through clay is important in industries such as oil and gas. In fact clay functions as a lid under which oil and gas collects in huge amounts in large oil reservoirs and often times act as a necessary predisposition for the existence of oil fields.

The drainage of oil wells is a complicated process where high pressures are utilized for pumping water and oil mixtures up towards the surface from deep underground aquifers. Here impermeable layers help build up necessary pressures through overburden stresses allowing the transformation from organic material toward hydrocarbon fossil fuels.

The overburden stressors and impermeable layers can lead to another phenomena called artesian wells.

Artesian wells

An important consideration when trying to identify potential locations for water extraction is the overburden pressures or internal fluid pressures in underground aquifers. These aquifers allow the flow of liquids over large distances and are typically separated by impermeable clay layers. The impermeable clay layers impose stresses on underlying layers resulting in increased internal water pressures. When trying to extract water from such configurations the resulting pressures in the liquid lead to the establishment of artesian wells see Figure 1-2.

An illustration of an artesian well, where the clay\impermeable layer is overlaying the aquifer layers.
Figure 1: Cross-section diagram of an artesian well, USA. Illustration published in Physical Geology by Mytton Maury (University Publishing Company, New York and New Orleans) in 1894. Digitally restored.
Location of the great artesian basin in Australia. The artesian basin is made of aquifers underlying impermeable layers such as clay.
Figure 2:The great artesian basin in Australia consisting of the largest artesian basin in the world spanning more than 1.7 million square kilometers.

The key defining characteristic between regular and artesian wells is the overburden stresses and internal fluid pressures. these allow for the easy extraction of liquids through since flow is automatic up to the surface meaning no need for pumping systems or otherwise extraction techniques.

Water in artesian wells

Artesian wells often contain water. This water is typically of high quality and easily drinkable as the aquifers functions as filtering material of harmful minerals and bacteria. Additionally water from artesian wells are often free from contaminant sources and thus often bottled as spring water more expensive than regular water from taps, examples of such include Fiji water among others.

Oil in artesian wells

In the beginning of the oil era, artesian wells played an important part for extraction of oil. The flowrate is large for aquifers allowing the extraction of huge amounts of oil and the artesian wells didn’t require expensive pumping instruments.

Additionally the locations of the artesian wells made extraction easily manageable as the land deposits at the time were full of oil. An example of such oil fields are displayed in GIF 1.

The land deposits were furthermore located in locations where large infrastructure existed making the pipeline laying easily manageable. This ensured that oil deposits kickstarted the production of oil in the United States within the first years of industrialization.

Clay for sculping

As a last addition clay is also fantastic for sculping sculptures. For the handy people around these sculptures are easily made utilizing a spinning wheel combined with sculpting clays such as monster sculpting clay.

The monster sculpting clay is exceptional for clay sculpting whether you are a beginner just trying it out for the first time or an experienced professional looking for a hard clay based mounding substrate to easily manipulate into beautiful structures or figures.


Mineral composition of clay, source.

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