Definition
Asbestos fibers are microscopic, thin, elongated particles less than 3 micrometers in diameter. They can stay airborne for extended periods and, once inhaled, penetrate deep into the lungs where the body cannot remove them. That persistence is what drives asbestos-related diseases. Fiber counting and identification underpin both exposure assessment and post-removal clearance testing.
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Asbestos
A commercial and regulatory label, not a mineralogical term, for a group of six naturally occurring fibrous silicate minerals of diverse geological origins, each extracted from different types of rock. The English name comes from the ancient Greek ásbestos (ἄσβεστος, "inextinguishable"), while Romance languages use "amianto" / "amiante", from Greek amíantos (ἀμίαντος, "incorruptible", "immaculate"); both names express the ancient awe at a material fire could not destroy. The six regulated minerals fall into two families: serpentine (chrysotile) and amphibole (crocidolite, amosite, anthophyllite, tremolite, actinolite). Asbestos was widely used in construction and manufacturing due to its heat resistance, tensile strength and insulating properties, with roughly 3,000 industrial applications at peak use in the 1970s. When disturbed, it releases microscopic fibres that lodge permanently in lung tissue, causing mesothelioma, lung cancer and asbestosis. All forms are classified as Group 1 human carcinogens by the IARC, and more than 70 countries have banned it.
Chrysotile (White Asbestos)
The most commonly used type of asbestos (CAS 12001-29-5), accounting for approximately 95% of asbestos found in buildings. Chrysotile is a serpentine mineral with curly fibers, also known as white asbestos. While historically considered less dangerous than amphibole asbestos, it is now recognized as carcinogenic and capable of causing mesothelioma and other asbestos-related diseases. Note: chrysotile should not be confused with chrysolite, a synonym for the mineral olivine (a completely different silicate). The similarity has caused persistent errors in print since at least 1909, when mineralogist John W. Evans proposed reviving the original Greek name karystiolite (from καρύστιος λίθος, "Karystian stone"), after the town of Karystos in Euboea, Greece, where fibrous serpentine was quarried in antiquity, the same stone Pliny called marmor carystium.
Amphibole Asbestos
A group of asbestos minerals with straight, needle-like fibers that are considered more harmful than chrysotile. Includes crocidolite (blue asbestos), amosite (brown asbestos), anthophyllite, tremolite, and actinolite. Amphibole fibers are more durable in lung tissue and are associated with higher rates of mesothelioma. These types are less common but more dangerous when exposure occurs.