Definition
One of the six regulated types of asbestos (CAS 77536-66-4), belonging to the amphibole mineral group. Actinolite forms long, thin, needle-like crystals that can be green, white, or grey. It was not used commercially as a standalone material but occurs as a contaminant in other minerals such as vermiculite and talc. When present in fibrous form, actinolite poses the same inhalation risks as other asbestos types, including mesothelioma and lung cancer.
See also:
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.
Tremolite
An amphibole asbestos mineral (CAS 77536-68-6) that forms white to dark-green prismatic crystals. Tremolite was not mined commercially for industrial use but is commonly found as a contaminant in chrysotile asbestos, vermiculite insulation (notably from the Libby, Montana mine), and talc products. Its presence as a contaminant has driven documented occupational and environmental exposure, and it is classified as a Group 1 carcinogen by the IARC.
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 amÃantos (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.