What is an Asbestos Mineral?
The asbestos mineral is a naturally occurring silicate mineral that is a type of fibrous silicate. These fibrous minerals are composed of thin fibre crystal. Each fibre is composed of a sub smaller unit known as fibrils. These fibrils can be released into the atmosphere by the erosion process like abrasion. These minerals are also called silica asbestos or asbestos silicate as they are made up of silicate units.
Asbestos Rock
As we know asbestos is a naturally occurring mineral, there are three main types of rock in which asbestos is found naturally. Therefore, these rocks are also called asbestos rock. These three main types of natural asbestos rock are:
Serpentine asbestos mineral
Amphibole
some mafic rocks.
1. Serpentine Asbestos Mineral
It is white in colour. The serpentine asbestos mineral is also known as chrysotile.
2. Amphibole
It includes actinolite asbestos rock, amosite asbestos rock (brown in colour), anthophyllite, crocidolite also known as a blue asbestos rock (blue in colour), and tremolite.
Other than the above-mentioned rocks, some other rocks are also present in the natural environment in which little amount of asbestos is found. These types of rock include metamorphosed dolostones, metamorphosed iron formations, carbonatites, and alkalic intrusions. Faulting and fracturing of these rocks Contribute to the formation of asbestos. These changes in the natural environment take place due to the increased temperatures, pressures, and the presence of water. The number of asbestiform minerals and asbestos in these rocks can range in size from commercial-grade ore bodies to thin impure veinlets or low-grade occurrences.
Asbestos can be released from these rocks to the atmosphere by the erosion process like rocks broken or crushed. Asbestos can also be released from asbestos-containing soils by stirring up.
Asbestos Mining
In India, there are more than thirty asbestos mining sites or mines that are in operation that produces around 2800 tones of asbestos silicate mineral per month. The main form of asbestos minerals produced from mining include; chrysotile and tremolite. In recent years a major quantity is imported from Canada that is around 70%. The quality of asbestos silicate minerals produced in India is very poor. Mining and milling and other related processes expose people to dreadful diseases like cancer and related diseases.
Asbestos Ore
The important asbestos ore:
Asbestos Chrysotile
Asbestos Amosite
Asbestos Crocidolite
Asbestos Tremolite
Asbestos Actinolite
Asbestos Anthophyllite.
Asbestos Mineral Uses
Asbestos is used in making the Chlor alkali diaphragm membrane.
It is used in making protective and decorative coating on the walls.
It is used in making fire blankets.
It is used in making stage curtains.
Asbestos is present in dental cast lining.
It is used in floor tiles.
It is used in cement building material.
It is used for making insulating mattresses and rope.
It is used in sprayed fire-proofing products.
It is used in making water and sewage pipes.
It is used in boilers.
It is used as an insulating material.
What are Asbestos-Related Problems?
Naturally occurring asbestos is not a health problem; it will cause problems only when it gets disturbed. Asbestos is composed of long silica fibres that are invisible to the naked eye. If asbestos mineral fibres are present in the air you breathe, you might inhale the asbestos fibres by your nose which can transfer to your lungs. Inhaling the fibres inside the body is the primary way to get exposed to the asbestos mineral. People living in a naturally occurring asbestos mineral area have a slight risk of asbestos-related disease. The chances of developing an asbestos-related disease vary from person to person. It depends upon the immunity of the person, a dose of the consumed asbestos mineral fibres, and the duration of the exposure. The number of fibres that have been breathed in and for how long, and fibre type alters the asbestos-related disease in a different person.
Some people can also be exposed to higher levels of asbestos at some times in their lives; for example in their workplace, community or home. Workers that work in the mines have also been known to develop asbestos-related diseases. These workers carry asbestos fibres home on their clothing, skin and hair. Asbestos can cause problems like:
It can develop pleural plaque.
It can cause chronic lung disease.
Asbestos can cause lung cancer.
It is responsible for causing mesothelioma.
Did You Know?
Asbestos was nicknamed "the magic mineral".
Asbestos occurs in some soils.
Asbestos is not considered a toxic mineral until it is left disturbed.
NOA is called naturally occurring Asbestos.
FAQs on Asbestos Mineral
1. What is asbestos and what is its basic chemical composition?
Asbestos is a collective name for a group of six naturally occurring fibrous silicate minerals. These minerals are known for their exceptional durability, fire resistance, and insulating properties. Chemically, they are primarily hydrated magnesium silicates, though the exact composition varies between different types. Their unique properties arise from their crystalline structure, where silicate units link together to form long, thin fibres.
2. What are the main types of asbestos minerals, and how do they differ?
Asbestos minerals are classified into two main groups based on their crystal structure:
- Serpentine Group: This group contains only one type, Chrysotile (white asbestos). Its fibres are curly and flexible, derived from a sheet-like silicate structure. Chrysotile was the most commercially used type of asbestos.
- Amphibole Group: This group includes five types, noted for their straight, needle-like fibres which are more brittle. These include Crocidolite (blue asbestos), Amosite (brown asbestos), Anthophyllite, Tremolite, and Actinolite. Amphibole fibres are considered more hazardous as they can penetrate deeper into lung tissue.
3. What were the common industrial uses of asbestos, and why were its properties so valued?
The unique properties of asbestos made it highly valued in over 3,000 industrial applications. Its key properties were high tensile strength, chemical inertness, and excellent thermal and electrical insulation. Common uses included:
- Building materials like roofing shingles, ceiling and floor tiles, and cement pipes.
- Automotive parts such as brake pads and clutch facings.
- Protective clothing and fireproof blankets.
- Insulation for pipes, boilers, and electrical wiring.
4. Why is asbestos considered a major health hazard, and what specific diseases does it cause?
Asbestos is a major health hazard because its microscopic fibres can be easily inhaled. Once in the lungs, these durable fibres resist the body's natural defenses and can remain lodged for a lifetime, causing inflammation and genetic damage. This long-term irritation can lead to several severe diseases, often decades after exposure:
- Asbestosis: A chronic lung disease caused by the scarring of lung tissue, leading to shortness of breath.
- Lung Cancer: The risk is significantly increased, especially for individuals who also smoke.
- Mesothelioma: A rare and aggressive cancer affecting the thin lining of the lungs (pleura) or abdomen, which is almost exclusively caused by asbestos exposure.
5. How does the fibrous silicate structure of asbestos give it unique properties like fire resistance?
The unique properties of asbestos are a direct result of its atomic structure. It is composed of repeating silicate tetrahedra (SiO₄⁴⁻). In asbestos, these tetrahedra link to form long, parallel chains or sheets. This molecular arrangement results in macroscopic fibres with high tensile strength. The strong silicon-oxygen (Si-O) covalent bonds within these structures are chemically and thermally stable, requiring a large amount of energy to break. This inherent stability is what gives asbestos its excellent resistance to heat, fire, and chemical degradation.
6. What is the key chemical difference between chrysotile (white asbestos) and amphibole asbestos types?
The primary chemical and structural difference lies in their silicate framework. Chrysotile is a magnesium silicate, Mg₃(Si₂O₅)(OH)₄, and belongs to the serpentine group. Its structure is based on rolled sheets of silicate tetrahedra, which results in its characteristic curly, flexible fibres. In contrast, amphiboles (like crocidolite) are complex inosilicates built from double chains of silicate tetrahedra. Their chemical formulas are more varied, incorporating cations like iron, sodium, and calcium, leading to straight, needle-like fibres.
7. How is asbestos formed naturally in rocks?
Asbestos minerals do not form on their own; they are the product of metamorphism. This geological process occurs when certain types of rock, known as ultramafic rocks (rich in magnesium and iron), are subjected to intense heat, pressure, and the presence of water. This process, often called serpentinization, alters the original minerals like olivine and pyroxene. The water facilitates the recrystallization of these minerals into the fibrous crystalline structures that we identify as asbestos.
