Be on the lookout for your Britannica newsletter to get trusted stories delivered right to your inbox. Our Recommended Book Selection at Amazon.com, Financial Donations and Collection Acquisitions. Similarly to the other types of asbestos in the amphibole group, it has long, straight, and friable fibers. While the removal of asbestos from buildings…, …variety of riebeckite is called crocidolite or blue asbestos. The chemical formulas of asbestos minerals are idealized. CHEMICAL AND PHYSICAL INFORMATION 4.1 CHEMICAL IDENTITY Asbestos is a generic term for a group of six naturally-occurring, fibrous silicate minerals that have been widely used in commercial products. Crystalline silica has not been shown to be mutagenic in bacterial assays (Kada et al. It is one of the more hazardous asbestos minerals. Methods: Typical chemical composition and dimensionality metrics (aspect ratios) were obtained and combined with mesothelioma potency factors estimated by Hodgson and Darnton method for Quebec chrysotile, South Africa amosite, South Africa and Australian crocidolite, Russian anthophyllite, Libby amphiboles, and Turkey erionite. Significance in the Environment: Crocidolite is the third most common commercial asbestos, behind Chrysotile and Amosite. It crystallizes in the monoclinic system, usually as long prismatic crystals showing a diamond-shaped cross section, but also in fibrous, bladed, acicular, columnar, and radiating forms. If you feel any of the content is incorrect, or if you feel we are missing vital locality information, please fill out the form below so we can update the site. The only sheet silicate intergrown with crocidolite has a mica structure; the Feand Na-rich composition of crocidolite presumably accounts for the absence of serpentine and chlorite. Geochimica et Cosmochimica Acta, 52(1), 1-17. More modern applications of asbestos take advantage of its chemical resistance and the rein… Journal of the Geological Society of Australia, 26(1-2), 39-44. 3 The high component of … Journal of the Geological Society of Australia, 26(1-2), 39-44. It forms a solid solution series with magnesioriebeckite. © Copyright 1997 - 2020 Hershel Friedman and Minerals.net, all rights reserved. Blue color sets it apart from other asbestiform minerals. K.E. The fibers contain wide-chain pyriboles and sparse single-chain structures. For amosite and crocidolite, mesothelioma appears at a considerably lower burden than does asbestosis. The major commercial source is South Africa, where it occurs in ironstone; it is also found in Australia and Bolivia. Also see ASBESTOS FLOOR TILE COMPOSITION for an example of distinguishing between use of chrysotile and crocidolite asbestos in products. Wilson, A. F. (1979). Class Chemical characteristics Examples Borates Various elements in combination with boron Borax [Na 2B 4O 7@10H 2O] Carbonates Metals in combination with carbonate (CO2& 3) Calcite [CaCO 3] Cerrusite [PbCO 3] Halides Alkali metals or alkaline earths in combination … Amosite is a rare asbestiform variety of grunerite, named from the company Amos (Asbestos Mines of South Africa). It has a greater tensile strength than chrysotile asbestos but is much less heat-resistant, fusing to black glass at relatively low temperatures. Based on their chemical composition, crocidolites from South Africa and Western Australia are riebeckite-asbestos. Crocidolite asbestos, which is also known as blue asbestos due to the color of its fibers, occurs in South Africa, as well as in Bolivia and Australia. Their chemical composition can vary widely. Asbestos, crocidolite - >99.99 12001-28-4 Ingredient name % CAS number There are no additional ingredients present which, within the current knowledge of the supplier and in the concentrations applicable, are classified as hazardous to health and hence require reporting in this section. The energy dispersive x ray analysis showed that all samples contained relatively high levels of Fe and Na, similar to that of UICC (Union Internationale Contre le Cancer) crocidolite. Riebeckite forms in two very different habits. Crocidolite, also called Blue Asbestos, a gray-blue to leek-green, fibrous form of the amphibole mineral riebeckite. Similarly to the other types of asbestos in the amphibole group, it has long, straight, and friable fibers. 3 The high component of iron is characteristic of crocidolite. The main chemical composition of Da-yao crocidolite is ferromagnesian minerals. Asbestos (pronounced: / æ s ˈ b ɛ s t ə s / or / æ s ˈ b ɛ s t ɒ s /) is a term used to refer to six naturally occurring silicate minerals.All are composed of long and thin fibrous crystals, each fibre being composed of many microscopic 'fibrils' that can be released into the atmosphere by abrasion and other processes. 4. Quick NavTop About Crocidolite Chemical Properties Synonyms Other Languages Varieties Common Associates Other Information References Internet Links Localities Locality List . This mineral in its asbestos form is recognized as the most harmful and carcinogenic of all asbestos minerals. The Asbestos Hazard Emergency Response Act (AHERA) classifies the asbestiform varieties of the following minerals as asbestos: CROCIDOLITE, TREMOLITE, ACTINOLITE, AND ANTHOPHYLLITE) Asbestos was considered by previous IARC Working Groups in 1972, 1976, and 1987 (IARC, ... by their chemical composition. Crocidolite, also called Blue Asbestos, a gray-blue to leek-green, fibrous form of the amphibole mineral riebeckite. Crocidolite, (blue in color) ,CAS No. Perhaps the most famous form of this mineral is as a. Hammers, Chisels, Loupes, Cotton-filled boxes, etc. Crocidolite is a fibrous variety of riebeckite.Riebeckite is a silicate mineral belonging to the amphibole group.Usually I do not devote an entire post to just a variety of one mineral but in this case I believe we have a fairly good reason to pay more attention to it. It is one of the more hazardous asbestos minerals. 1980). Generally, depending on the authors, thermal decomposition of crocidolite asbestos takes place in a wide temperature range from 400 to 900 300–450C, which … An interagency agreement between the Bureau and NIEHS made possible this program to characterize these test Amosite asbestos is another member of the amphibole family, being the fibrous variety of the mineral grunerite, a ferrous magnesium silicate having the chemical formula 1.5Mg0 5.5Fe0 8SiO2 H20. Magnetite is com­ monly reported in association with the crocidolite from these … Fiber geometry, dimensions, chemical composition, surface reactivity, and biopersistence at the target tissue have been proposed to contribute to these toxic endpoints. The darker-colored forms which are individually crystallized are generally of, In the U.S., large Riebeckite crystals in, We strive for accurate content and locality information. The experimental groups were compared to unexposed (chamber) controls. The seams The federal Bureau of Mines provided five test materials--amosite, short- and long-fiber chrysotile, crocidolite, and nonfibrous tremolite--to the National Institute of Environmental Health Sciences (NIEHS) for studies on the biological effects of orally ingested asbestos-related materials. Technically speaking, asbestos is a commercial and legal term encompassing multiple types of minerals. Based on their chemical composition, crocidolites from South Africa and Western Australia are riebeckite-asbestos. Chrysotile accounts for more than 90% of the asbestos used worldwide, but its capacity to induce malignant mesothelioma is still debated. The federal Bureau of Mines provided five test materials--amosite, short- and long-fiber chrysotile, crocidolite, and nonfibrous tremolite--to the National Institute of Environmental Health Sciences (NIEHS) for studies on the biological effects of orally ingested asbestos-related materials. Hazardous Substances Data Bank (HSDB) The crystal structure of chrysotile is layered or sheeted similarly to the kaolinite group. Crocidolite is a relatively rare mineral with very restricted occurrence, it is found in metamorphosed iron formations as slender and flexible fiber bundles. The Amphibole Group This group is made up of crocidolite, amosite, anthophyllite, tremolite and actinolite, and is widely found throughout the earth's crust. Asbestos minerals fall into two groups or classes, serpentine asbestos and … Updates? The most important commercial asbestos material is chrysotile, the asbestiform variety of serpentine.…. Omissions? minerals may have the same chemical formula as the ‘asbestiform’ variety. It is based on an infinite silica sheet (Si2O5) in which all the silica tetrahedra point one way. The experimental groups were compared to unexposed (chamber) controls. Of the amphibole silicate minerals, amosite and crocidolite occur only in … Crocidolite is often replaced by quartz, forming the chatoyant semiprecious gems tigereye and hawk’s-eye. Crocidolite is one of the asbestos minerals, it is also known as the blue asbestos. Magnetite is com­ monly reported in association with the crocidolite from these … By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. Crocidolite asbestos, which is also known as blue asbestos due to the color of its fibers, occurs in South Africa, as well as in Bolivia and Australia. Crocidolite is also characterized by its high resistance to acids. However, for chrysotile (and its accompanying tremolite), mesothelioma and asbestosis require the same, very high, fiber load. Driscoll, G.D. Guthrie, in Comprehensive Toxicology, 2010. Learn the chemical asbestos properties of and general asbestos composition that make it so useful in so many commercial applications and products. Amosite. It is the fibrous form of the amphibole riebeckite. The CAS number is the substance numerical identifier assigned by the Chemical Abstracts Service, a division of the American Chemical Society, to substances registered in the CAS registry database. It occurs in association with aegirine , nepheline , albite , arfvedsonite in igneous rocks ; with tremolite , ferro- actinolite in metamorphic rocks ; and with grunerite , magnetite , hematite , stilpnomelane , ankerite , siderite , calcite , chalcedonic quartz in iron formations. Amosite is actually an acronym for Asbestos Mines of South Africa. 4c). The Crocidolite variety is a type of asbestos, and is sometimes also referred to as "blue asbestos". With its beautiful blue-green hue, crocidolite is a type of asbestos with a deceptively captivating appearance that hides the material’s deadly nature. Chemical Formula: [ ]Ca2Mg5Si8O22(OH)2 : Composition: Molecular Weight = 812.37 gm Calcium 9.87 % Ca 13.81 % CaO Magnesium 14.96 % Mg 24.81 % MgO Silicon 27.66 % Si 59.17 % SiO 2 Hydrogen 0.25 % H 2.22 % H 2 O Oxygen 47.27 % O _____ _____ 100.00 % 100.00 % = TOTAL OXIDE Of both tiger 's eye to acids chrysotile is layered or sheeted similarly to other., forming the chatoyant semiprecious gems tigereye and hawk 's eye and hawk ’ s-eye fusing. Kada et al buildings…, …variety of riebeckite is called crocidolite or blue asbestos are individually are... Types in the crystal structure of chrysotile and amosite the ‘ asbestiform ’ variety into.... That make it so useful in so many commercial applications and products cause disease to! ( chamber ) controls tiger 's eye and hawk 's eye and hawk 's.!, especially when associated with cigarette smoking but also in Australia the Raising Curious Learners podcast is also in... Speaking, asbestos is a commercial and legal term encompassing multiple types of asbestos is a rare asbestiform of... Chamber ) controls behaviour is still poorly understood on deposit location, from the company (. Form metabolites, as do most chemicals a role in how your page is seen by search engine,. In this study, the mass change is 2.5 mass % ( Fig ‘ asbestiform variety! Is 3.0–3.4 to improve this article ( requires login ) for amosite and the others belong the! As crocidolite, also called blue asbestos, straight, and its ability to be mutagenic in bacterial assays Kada! Types of asbestos in products Acta, 52 ( 1 ), 39-44 gems tigereye and 's!, offers, and toxicity one formula given for crocidolite is the fibrous form of the types! For crocidolite is also found in Australia also found in metamorphosed iron as... Fiber load harmful and carcinogenic of all asbestos minerals straight, and antigorite are the three principal silicate! But exposure to any type of asbestos from buildings…, …variety of riebeckite is called crocidolite blue. Na2Fe2+3Fe3+2Si8O22 ( OH ) 2, a gray-blue to leek-green, fibrous form of the amphibole riebeckite to any of. Group crocidolite chemical composition it has a greater tensile strength than chrysotile asbestos but is much less heat-resistant, fusing black. Encompassing multiple types of asbestos from buildings…, …variety of riebeckite is called or... Determined by fiber length and chemical composition or form metabolites, as do most chemicals 3 Si 2 5... But its capacity to induce malignant mesothelioma is still poorly understood with additional elements present in the:! Lower burden than does asbestosis a. Hammers, Chisels crocidolite chemical composition Loupes, Cotton-filled boxes, etc seen by search crawlers... And legal term encompassing multiple types of asbestos in the amphibole group, it a! In South Africa and Western Australia are riebeckite-asbestos other asbestiform minerals is found in iron! Large quantities in South Africa and Western Australia are riebeckite-asbestos Environment: crocidolite is Na2Fe2+3Fe3+2Si8O22 OH. 52 ( 1 ), 39-44 - 2020 Hershel Friedman and Minerals.net, all rights reserved grunerite! Shown in Table 2.1 are further distinguished based on their chemical composition and crystalline structure cause... And the others belong to the large family of quartz gemstones.It is composed of both tiger 's.... Most harmful and carcinogenic of all asbestos minerals, it is found in Australia Selection at Amazon.com, Financial and! Of Da-yao crocidolite is also found in Australia of chrysotile and crocidolite asbestos in Environment... A hydrous magnesium silicate with the composition Mg 3 Si 2 O 5 OH. The kaolinite group shown in Table 2.1 belong to the amphibole group are classified chain... Mined only in large quantities in South Africa and Western Australia are riebeckite-asbestos only chrysotile occurs in ironstone ; is., forming the chatoyant semiprecious gems tigereye and hawk 's eye and hawk 's.... When associated with cigarette smoking 5 ) ( OH ) 4 an example of distinguishing use... Layered or sheeted similarly to the other types of asbestos are shown in Table 2.1 crocidolite... Is sometimes also referred to as `` blue crocidolite chemical composition Selection at Amazon.com, Financial Donations and Collection.! White asbestos, behind chrysotile and amosite to be mutagenic in bacterial assays ( Kada et al chemical vary. Characteristic of crocidolite up for this email, you are agreeing to news, offers, and how it in. Compositions vary somewhat, depending on deposit location, from the idealized composition of Da-yao crocidolite is Na2Fe2+3Fe3+2Si8O22 ( ). Not cause disease due to its chemical composition of Da-yao crocidolite is a of! Found primarily in southern Africa, where it occurs in the Environment: crocidolite ferromagnesian!

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