Types of Asbestos
Asbestos is a group of naturally-occurring silicate minerals with six types that have been used commercially. Each type has unique properties that have proven useful in specific applications. However, there is no safe method for manufacturing or using asbestos products, and all types of asbestos pose grave health dangers to humans.
Legally Reviewed By: Sam E. Taylor
Managing Attorney | Mesothelioma & Asbestos in Houston
- Page Last Updated:
- April 30, 2024
Legally Reviewed By: Sam E. Taylor
Managing Attorney | Mesothelioma & Asbestos in Houston
- Page Last Updated:
- April 30, 2024
Asbestos is a generic term for bundles of naturally-occurring fibrous mineral silicates that occur in the serpentine and amphibole families. These fibers are extremely flexible with a small diameter, large length, and splaying ends that make it easy to separate the fibers.
When used industrially, asbestos occurs in two forms: friable and non-friable. Friable asbestos is easy to crumble and, therefore, prone to becoming airborne. Non-friable asbestos, on the other hand, is encapsulated so that its fibers do not easily become airborne. Non-friable asbestos can become friable when power tools are used to cut or repair the containing components.
The six types of asbestos listed by the National Institute for Occupational Safety and Health (NIOSH) that are most commonly used commercially include the following:
- Chrysotile
- Crocidolite
- Amosite
- Actinolite
- Tremolite
- Anthophyllite
Chrysotile Asbestos
Also known as white asbestos, chrysotile asbestos is the primary form of asbestos used commercially, accounting for approximately 95 percent of all commercial and industrial use and, thus, the most commonly encountered in cases of asbestos exposure. Chrysotile is the sole form of asbestos in the serpentine group of minerals.
According to Micro Analytical Laboratories, chrysotile asbestos is comparable to fine threads or hairs that are curved, wavy, or kinked. Occasionally, chrysotile fibers are straight. The fibers are usually long and very flexible. Shorter chrysotile fibers tend to be thicker and more brittle.
The most useful characteristics of chrysotile asbestos are its tensile strength, resistance to extreme temperatures, chemical resistance, and flexibility of the fibers. It is also so stain-resistant that it was often used in the construction of stain-resistant laboratory bench tops. Its flexibility is useful in textiles due to the ease of spinning the ultra-flexible fibers.
Products
Commercial products that use chrysotile asbestos include the following, according to the Federal Register and Penn Medicine:
- Diaphragms in the chlor-alkali industry
- Sheet gaskets in chemical production
- Brake blocks
- Brakes and linings
- Asphalt
- Vehicle friction parts, such as brake pads and clutches
- Gaskets
- Plastics
- Roofing materials
- Rubber textiles
Crocidolite Asbestos
Crocidolite is the asbestos mineral, or asbestiform, of the group of minerals known as riebeckite. Crocidolite is also known as blue asbestos and ranges in color from Prussian blue to indigo and may appear as yellow-green. It is also occasionally dark blue or black, according to NIOSH.
Crocidolite asbestos may appear as different colors from different viewing angles, a quality known as pleochroism. It is slightly more brittle than chrysotile but, according to NIOSH, is still flexible enough to be useful for spinning and weaving.
Crocidolite is in the amphibole family. It is harder than the other amphibole varieties, and the fibers may be curved or straight. Like other asbestiforms in this family, crocidolite is sharp and needle-like.
Products
According to Penn Medicine, crocidolite was commonly used in the following products:
- Cement
- Tiles
- Insulation materials
A study by Cancer Research also found that crocidolite asbestos was used in the filters of the original Kent Micronite brand of cigarettes from 1952 to 1956, exposing smokers of this brand to substantial amounts of asbestos.
Amosite Asbestos
Amosite is the commercial name for grunerite, an amphibole-family form of asbestos that occurs in the cummingtonite-grunerite series of minerals.
This type of asbestos is often referred to as brown asbestos, but it can range in color from weak green to brown, changing in color range from yellow to reddish brown when heated at high temperatures for a long period of time.
This form of asbestos consists of very long, thin fibers and fiber bundles that are moderately brittle and often arched. It often forms bundles that resemble broom tails and is prone to separating into small groups of fibers that are needle-like. Rather than fraying at the ends, the ends are typically flat or knifelike.
Products
According to Penn Medicine, amosite is typically used in products such as the following:
- Cement
- Chemical and electrical insulation
- Fire protection
- Gaskets
- Insulation boards
- Plumbing insulation
- Roofing
- Thermal insulation
- Tiles
Actinolite Asbestos
A member of the amphibole group, actinolite is dark-colored, ranging from bright to grayish green, and has needle-like fibers. It is found in the mineral series tremolite-ferro-actinolite.
Products
According to Penn Medicine, actinolite has been used in the following products:
- Cement
- Insulation
- Paints
- Sealants
- Drywall
Tremolite Asbestos
Tremolite is in the amphibole family. The difference between tremolite and actinolite is the magnesium and iron levels, according to Micro Analytical Laboratories.
Tremolite has higher magnesium content and appears white, pink, or pale violet.
According to NIOSH, tremolite can appear as an asbestiform and non-asbestiform variety. The asbestiform variety of tremolite is also known as byssolite. Tremolite occurs in the tremolite-ferro-actinolite family of minerals, often in metamorphic rocks such as dolomitic limestone and talc deposits.
Products
According to Penn Medicine, tremolite asbestos has been found in the following products:
- A contaminant of talc and vermiculite
- Paint
- Sealants
- Insulation
- Roofing
- Plumbing materials
Anthophyllite Asbestos
Anthophyllite asbestos is an amphibole asbestiform.
This type of asbestos is rarely used in building materials. Its shape resembles a knife blade that comes to a point at one end. The fibers are long, needle-like, and flat. It is mined in Finland, Canada, and parts of the United States.
Products
According to Penn Medicine, anthophyllite asbestos has been used in the following building products:
- Cement
- Insulation
