What is Asbestos? Get the Key Facts

What is asbestos? Is it man-made or is it natural? Find out everything you need to know about asbestos below. If you have any unanswered questions, please request a callback.

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What is Asbestos?

Asbestos is the name given to several naturally occurring silicate minerals which are fibrous.

These minerals have been heavily utilised and exploited for their seemingly “magical” properties.

Asbestos is derived from a Greek term meaning 'unquenchable' or 'inextinguishable'.

The fibrous mineral group has been used for centuries, particularly peaking in the 20th century, due to its favourable properties, including high tensile strength, flexibility, resistance to heat and chemicals, and electrical resistance.

Known for their durability, asbestos minerals have been used in numerous industries. However, their inhalation is associated with several health hazards, leading to serious diseases.

3 Most Commonly Used Types of Asbestos

Chrysotile (White) Asbestos

Amosite (Brown) Asbestos

Crocidolite (Blue) Asbestos

3 Less Commonly Used Types of Asbestos

Fibrous Anthophylite

Fibrous Tremolite

Fibrous Actinolite

The Six Asbestos Types and Their Chemical Compositions


Chrysotile, or white asbestos, belongs to the serpentine group of minerals. It is a hydrated magnesium silicate, with the chemical formula Mg3(Si2O5)(OH)4. The curly and flexible structure of chrysotile fibres can be attributed to its layered silicate mineral structure.

Chrysotile is the most commonly used type of asbestos. It's composed of fine, curly fibres and is primarily sourced from Canada and Russia. Chrysotile has been widely used in roofs, ceilings, walls, and floors of homes and businesses. It was also once used in brake linings, gaskets, and boiler seals.


Amosite, or brown asbestos, is part of the amphibole group. Its chemical composition is (Fe,Mg)7Si8O22(OH)2. The iron content in amosite gives it its brown colour and high heat resistance.

Amosite is a trade name for the amphiboles belonging to the cummingtonite-grunerite mineral series. It was predominantly mined in South Africa. This asbestos type is known for its exceptional heat resistance and tensile strength, which led to its use in cement sheets, pipe insulation, and fire protection. Amosite fibres are straight and brittle, making them more prone to becoming airborne and inhaled, and thus more dangerous than chrysotile.


Crocidolite, or blue asbestos, is another member of the amphibole group. Its chemical formula is Na2Fe2+3Fe3+2Si8O22(OH)2. It is the fibrous form of the mineral riebeckite. Crocidolite fibres are thin and straight, and their blue colour is due to the iron in its structure.

Crocidolite is considered (by some academics) the most hazardous form of asbestos. This mineral, abundant in Australia, South Africa, and Bolivia, has extremely thin fibres that can be easily inhaled and embedded in lung tissues. Crocidolite has been used in a variety of products, including pipe insulation, spray-on coatings, and cement products.


Tremolite asbestos, while not commercially used, is also an amphibole mineral with the chemical formula Ca2(Mg5.0-4.5Fe2+0.0-0.5)Si8O22(OH)2. It can vary in colour due to impurities in its structure.

Tremolite asbestos was not used commercially, but it can be found as a contaminant in chrysotile asbestos, talc powders, and vermiculite products.

It exists in several forms and colours, ranging from white to dark green. Tremolite fibres are highly heat resistant and can be woven, leading to occasional use in certain insulating materials.


Actinolite asbestos is part of the amphibole group of minerals, with the chemical composition of Ca2(Mg4.5-2.5Fe2+0.5-2.5)Si8O22(OH)2. Actinolite contains more iron than tremolite, contributing to its darker colour.

Actinolite asbestos is dark in colour and has a straight, brittle structure similar to amosite. While not commercially valuable, it can be found as a contaminant in some products, including vermiculite insulation and gardening products.

Its fibres are lightweight and can easily become airborne if disturbed.


Anthophyllite asbestos, an amphibole mineral, has the chemical formula of (Mg,Fe2+)7Si8O22(OH)2. The level of iron and magnesium in anthophyllite can vary, affecting its colour and other properties.

Anthophyllite asbestos, primarily sourced from Finland, is one of the rarest forms and was not commonly used in commercial products.

Its fibres are grey or white, and it has been occasionally used in composite flooring.

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Why was asbestos used?

Asbestos was extensively used because of its unique properties. These properties include

Incredible Heat ResistanceAsbestos has an incredible resistance to heat. It does not burn or melt until it gets to an extremely high temperature, somewhere around 1,500°C. That’s more than plaster, more than fibreglass and even more than steel. 

Ultimate Insulator -  It is an excellent insulator and does not easily allow heat, electricity, light or sound to pass through it.

Super Strong -  Asbestos is super strong and has a tensile strength that surpasses steel.

Insoluble in water -  Asbestos is insoluble in water, which means it can’t be dissolved in water.

Immense Chemical Resistance -  Asbestos can resist the destructive effects of powerful acids and alkalines.

Tasteless -  Asbestos has no detectable aroma or taste.

Flexible -  Asbestos is flexible, meaning it can bend easily without breaking. It can be spun and woven to make items like textiles, ropes and woven products.

However, the over-riding factor which lead to the high use of asbestos was cost – asbestos was cheap.

*Information supplied by Asbestos The Dart Arts 

What is asbestos 1
What is asbestos

Why is asbestos hazardous?

Asbestos is a hazard because of a unique process. Asbestos strands can be split into smaller and thinner fibres during disturbance.

Asbestos mined ore will initially divide into visible strands, fibre bundles, and individual fibres. This splitting can continue on to minute levels of microscopic size. This process is unique to asbestos and is why airborne asbestos is such a problem.

Asbestos fibres can become so small that they remain airborne longer and pass undetected by the respiratory dust defences. These microscopic fibres may become inhaled into the lungs.

Once in the lungs, because of their properties such as chemical resistance, asbestos fibres are also resistant to the human body’s natural defence mechanisms.

As such, asbestos fibres remain within the body and may cause significant health problem

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