Six minerals are defined as "
asbestos" including:
chrysotile,
amosite,
crocidolite,
tremolite,
anthophyllite and
actinolite.
Chrysotile, CAS No. 12001-29-5, is obtained from serpentine rocks which are common throughout the world. Its idealized chemical formula is Mg3(Si2O5)(OH)4. Chrysotile fibers are curly as opposed to fibers from amosite, crocidolite, tremolite, actinolite, and anthophyllite which are needlelike.Chrysotile, along with other types of asbestos, has been banned in dozens of countries and is only allowed in the United States and Europe in very limited circumstances. Chrysotile has been used more than any other type and accounts for about 95% of the asbestos found in buildings in America. Applications where chrysotile might be used include the use of joint compound. It is more flexible than amphibole types of asbestos; it can be spun and woven into fabric. The most common use is within corrugated asbestos cement roof sheets typically used for outbuildings, warehouses and garages. It is also found as flat sheets used for ceilings and sometimes for walls and floors. Numerous other items have been made containing chrysotile including brake linings, cloth behind fuses (for fire protection), pipe insulation, floor tiles, and rope seals for boilers.
Amosite, CAS No. 12172-73-5, is a trade name for the amphiboles belonging to the Cummingtonite - Grunerite solid solution series, commonly from Africa, named as an acronym from Asbestos Mines of South Africa. One formula given for amosite is Fe7Si8O22(OH)2. It is found most frequently as a fire retardant in thermal insulation products and ceiling tiles.
Crocidolite, CAS No. 12001-28-4 is an amphibole found primarily in southern Africa, but also in Australia. It is the fibrous form of the amphibole riebeckite. One formula given for crocidolite is Na2Fe2+3Fe3+2Si8O22(OH)2.
Notes: chrysotile commonly occurs as soft friable fibers. Asbestiform amphibole may also occur as soft friable fibers but some varieties such as amosite are commonly straighter. All forms of asbestos are fibrillar in that they are composed of fibers with widths less than 1 micrometer that occur in bundles and have very long lengths. Asbestos with particularly fine fibers is also referred to as "amianthus". Amphiboles such as tremolite have a crystal structure containing strongly bonded ribbonlike silicate anion polymers that extend the length of the crystal. Serpentine (chrysotile) has a sheetlike silicate anion which is curved and which rolls up like a carpet to form the fiber.
Chrysotile asbestos - Also called white asbestos, chrysotile asbestos is viewed to be the safest of the six because it is less friable (less brittle / likely to produce airborne microbes) and therefore less likely to be inhaled. More than 95% of asbestos used today is of the chrysotile variety. Some early evidence suggested that chrysotile asbestos did not pose a health hazard even when inhaled, though more recent animal studies have dispelled this myth. Chrysotile is the only type of asbestos classed as a serpentine mineral (fibers making up chrysotile are of a curled variety).
The remaining five types of asbestos are amphibole minerals, meaning that they are made up of straight, needle-like fibers.
- Tremolite asbestos - Tremolite asbestos is not often used industrially, though it was sometimes found in certain commercial products such as talcum powder.
- Actinolite asbestos - Like tremolite, actinolite asbestos is not often used industrially. Airborne actinolite asbestos fibers are easily inhaled and severely damaging to the lungs.
- Amosite asbestos - Also called brown asbestos, amosite asbestos is used for a variety of commercial purposes such as pipe and cement sheet insulation.
- Crocidolite asbestos - Also called blue asbestos, crocidolite asbestos viewed as the most dangerous of the six.
- Anthophyllite asbestos - Like tremolite and actinolite, anthophylite asbestos is not often used industrially, though it can occasionally be found in certain types of vermiculite (natural minerals that expand with the application of heat).
Source:
Mesothelioma Research Foundation Of America
www.mesorfa.orgSix minerals are defined as "asbestos" including: chrysotile, amosite, crocidolite, tremolite, anthophyllite and actinolite.
White Asbestos
Chrysotile, CAS No. 12001-29-5, is obtained from serpentine rocks which are common throughout the world. Its idealized chemical formula is Mg3(Si2O5)(OH)4. Chrysotile fibers are curly as opposed to fibers from amosite, crocidolite, tremolite, actinolite, and anthophyllite which are needlelike.Chrysotile, along with other types of asbestos, has been banned in dozens of countries and is only allowed in the United States and Europe in very limited circumstances. Chrysotile has been used more than any other type and accounts for about 95% of the asbestos found in buildings in America. Applications where chrysotile might be used include the use of joint compound. It is more flexible than amphibole types of asbestos; it can be spun and woven into fabric. The most common use is within corrugated asbestos cement roof sheets typically used for outbuildings, warehouses and garages. It is also found as flat sheets used for ceilings and sometimes for walls and floors. Numerous other items have been made containing chrysotile including brake linings, cloth behind fuses (for fire protection), pipe insulation, floor tiles, and rope seals for boilers.
Brown Asbestos
Amosite, CAS No. 12172-73-5, is a trade name for the amphiboles belonging to the Cummingtonite - Grunerite solid solution series, commonly from Africa, named as an acronym from Asbestos Mines of South Africa. One formula given for amosite is Fe7Si8O22(OH)2. It is found most frequently as a fire retardant in thermal insulation products and ceiling tiles.
Blue Asbestos
Crocidolite, CAS No. 12001-28-4 is an amphibole found primarily in southern Africa, but also in Australia. It is the fibrous form of the amphibole riebeckite. One formula given for crocidolite is Na2Fe2+3Fe3+2Si8O22(OH)2.Notes: chrysotile commonly occurs as soft friable fibers. Asbestiform amphibole may also occur as soft friable fibers but some varieties such as amosite are commonly straighter. All forms of asbestos are fibrillar in that they are composed of fibers with widths less than 1 micrometer that occur in bundles and have very long lengths. Asbestos with particularly fine fibers is also referred to as "amianthus". Amphiboles such as tremolite have a crystal structure containing strongly bonded ribbonlike silicate anion polymers that extend the length of the crystal. Serpentine (chrysotile) has a sheetlike silicate anion which is curved and which rolls up like a carpet to form the fiber.
Chrysotile asbestos - Also called white asbestos, chrysotile asbestos is viewed to be the safest of the six because it is less friable (less brittle / likely to produce airborne microbes) and therefore less likely to be inhaled. More than 95% of asbestos used today is of the chrysotile variety. Some early evidence suggested that chrysotile asbestos did not pose a health hazard even when inhaled, though more recent animal studies have dispelled this myth. Chrysotile is the only type of asbestos classed as a serpentine mineral (fibers making up chrysotile are of a curled variety).
The remaining five types of asbestos are amphibole minerals, meaning that they are made up of straight, needle-like fibers.
Tremolite asbestos - Tremolite asbestos is not often used industrially, though it was sometimes found in certain commercial products such as talcum powder.
Actinolite asbestos - Like tremolite, actinolite asbestos is not often used industrially. Airborne actinolite asbestos fibers are easily inhaled and severely damaging to the lungs.
Amosite asbestos - Also called brown asbestos, amosite asbestos is used for a variety of commercial purposes such as pipe and cement sheet insulation.
Crocidolite asbestos - Also called blue asbestos, crocidolite asbestos viewed as the most dangerous of the six.
Anthophyllite asbestos - Like tremolite and actinolite, anthophylite asbestos is not often used industrially, though it can occasionally be found in certain types of vermiculite (natural minerals that expand with the application of heat).
Source: Mesothelioma Research Foundation Of America www.mesorfa.org