Asbestos is a generic term for a group of crystalline mineral silicates that occur naturally in various forms. In its natural state and is known as amosite mineral grunerite commercially referred to as grunerite asbestos amosite, or brown. The crystals are monoclinic prismatic. However the … The analyser is then inserted (to give crossed- [ Top] [ Japanese] Grunerite [abbr. Its chemical composition is (Mg, Fe, Mn) 7 [Si 8 O 22](OH) 2. Amosite was commonly mined in South Africa in its natural type, Grunerite. The regulated amphiboles are often referred to by generic names. 4, see reference paper) around 660 cm -1 , more exactly at 665 cm -1 for the grunerite samples of this work and at 663 cm -1 and … 20cm x 6.5cm x 6cm Grunerite, Hematite (Var: Specularite) Riebeckite asbestos is also known as crocidolite or blue asbestos while grunerite asbestos is known as amosite or brown asbestos. Amosite. Grunerite became commercially known as amosite because one of the most important suppliers of this form of asbestos was the Asbestos Mines of South Africa or AMOSA as these mines were commonly called. Commonly known as brown asbestos, the texture of amosite fibres is characterised by their sharp, brittle, needle-like fibres and brownish-grey colour. Tremolite … Asbestos, any of several minerals that readily separate into long, flexible fibres. The luster is glassy to pearly with colors ranging from green, brown to dark grey. The crystals are monoclinic prismatic. Amosite was also historically known as: "brown asbestos". Asbestos, Amosite Asbestos, grunerite ACGIH TLV (United States, 3/2019). It is the next most common commercial asbestos after Chrysotile. Include approximate length and width of fibers, color, and general appearance. It was at one time, … Was extracted from approximately 80,000 tons of amosite in the province of Transvaal in South Africa by the year 1970. Grunerite (Amosite) Texture: asbestiform(a) Color: grey-brown in hand specimen, α′ colorless, γ′ colorless to very light brown Birefringence: medium (nγ′ - nα′ = 0.023) (b) Extinction: mostly parallel Sign of Elongation: positive Concentration of Asbestos(c): > 90 % by weight or volume Form: Respirable fibers: length greater than 5 uM; aspect ratio equal to or greater than 3:1 as determined by the membrane filter method at 400-450X magnification (4-mm objective) phase contrast illumination. Other asbestos types are less pleochroic, with actinolite usually pale green (parallel) and amosite light brown. All three minerals' formulae are essentially the same: (Mg, Fe)7Si8O22(OH)2. For each grunerite spectrum, the peaks are listed below with all assignments. Grunerite is monoclinic and typically weakly colored in green or brown in plane light. It was discovered in 1853 and named after Emmanuel-Louis Gruner (1809–1883), a Swiss-French chemist who first analysed it. The Mohs hardness is 5 to 6 and the specific gravity is 3.4 to 3.5. Iron-free varieties of tremolite containing manganese can have a lavender colour. Significance in the Environment: Amosite is a hazardous material and exposure should be very carefully limited. Gru ] Year of discovery: 1853 (Sarvengude ravine, France), 1894 (Japan) Locality list: 18 localities of grunerite Fe 7 Si 8 O 22 (OH) 2 [][Fe 2+ 2][Fe 2+ 5][(OH) 2 |(Si 4 O 11) 2] 14-; Class: Mg-Fe-Mn amphibole subgroup w(OH,F,Cl)-dominant amphibole group Amphibole supergroup Class: … Typically observed in hues of beige, tan, and brown, amosite is mineralogically known as asbestiform grunerite or from the amphibole cummingtonite-grunerite mineral series. The commercial production of amosite, or “brown” asbestos, ended within the last decade and this type of asbestos is no longer mined. Shows shiny splays silver, gold and rose coloured. Anthophyllite is gray to various shades of green and brown. Iron-rich grunerite fibers may have colors ranging from very pale yellow to light brown. General Grunerite Information : Chemical Formula: [ ]Fe++7Si8O22(OH)2 : Composition: Molecular Weight = 1,001.61 gm Iron 39.03 % Fe 50.21 % FeO: Silicon 22.43 % Si 47.99 % SiO 2: Hydrogen 0.20 % H 1.80 % H 2 O: Oxygen 38.34 % O: 100.00 % 100.00 % = TOTAL OXIDE OSHA PEL (United … They result when siliceous minerals are leached out of rock by water and then re-crystallize in spaces within the parent rock as compound metallic silicates. The amphibole class of asbestos have straight, needle-like fibres that present an especially high risk of damaging the lungs when inhaled. Chrysotile, the fibrous form of the mineral serpentine, is the best-known type and accounts for about 95 percent of all asbestos in commercial use.It is a hydrous magnesium silicate with the chemical composition of Mg 3 Si 2 O 5 (OH) 4.The … Amosite was used industrially for various purposes such as cement sheet and pipe … Amosite asbestos is a less common form of asbestos and is also known as brown asbestos or Grunerite. If amosite is confirmed by this test, go to step 15 for quantitative estimation, otherwise continue. Amosite: Amosite asbestos is primarily sourced in South Africa. The seams break down readily to yield long, somewhat harsh fibers, brownish-yellow to almost white in color depending … The Mohs hardness is 5 to 6 and the specific gravity is 3.4 to 3.5. If the morphology matches amosite, examine the fibers using the dispersion staining objective. Also called Grunerite or brown asbestos, amosite asbestos is an amphibole originating in Africa. These include the serpentine mineral chrysotile (also known as ‘white asbestos’), and the five amphibole minerals – actinolite, amosite (also known as ‘brown asbestos’), anthophyl- lite, crocidolite (also known as ‘blue asbestos’), and tremolite (IARC, 1973; USGS, 2001). Amosite asbestos is the fibrous form of amphibole in the cummingtonite-grunerite family. It was discovered in 1853 and named after Emmanuel-Louis Gruner (1809–1883), a Swiss-French chemist who first analyzed it. There are various morphological types that differ in their mechanical, chemical and toxicological properties [1–3]. Table 1 lists those that com… Grunerite is also known commercially by the name amosite from the name Asbestos Mines Of … It often appears brown in color and its fibers are shorter and straighter than chrysotile fibers. The name derives from the origin where most of this mineral was mined, in the Asbestos Mines of South Africa. Fiber bundles have splayed ends and “kinks”. Asbestos pipe insulation in buildings - used on heating pipes, water pipes, and on occasion drains - How to make a visual identification of asbestos insulation without laboratory tests Asbestos pipe insulation, still in use or abandoned on building pipes, compared with fiberglass pipe insulation Asbestos pipe insulation, insulated over … Amosite Asbestos. Amosite asbestos, also known as “brown asbestos” and grunerite, is a type of amphibole asbestos. A narrow translucent quartz vein crosses the middle of the specimen. Crocidolite appears blue (parallel) and grey (perpendicular). These spectra are very similar – the ν 1 (A 1g ) symmetric stretching (ν s ) of the Si-O b -Si bridge is shown in all spectra (fig. Morphology, color a Refractive indices b Birefring- ence Extinction Sign of elonation; α γ; Chrysotile (asbestiform serpentine) Wavy fibers. colour and pleochroism (colour in relation to the orientation of the polarised light) can be observed. Glaucophane and riebeckite are usually blue. The cummingtonite-grunerite series occurs in various shades of light brown. Amosite asbestos also called as brown asbestos, due to its gray to brown color, or Grunerite. Amosite’s distinctive brown or earthy grey colour comes from its high iron content. Amosite Asbestos The U.S. Environmental Protection Agency determined amosite, or “brown asbestos,” to be the second most commonly used type of asbestos in the United States. TWA: 0.1 f/cc 8 hours. This type of asbestos is particularly strong and heat resistant, as well as possessing extreme insulation … The luster is glassy to pearly with colors ranging from green, brown to dark grey. White or greenish (chrysotile), blue (crocidolite), or gray-green (amosite) fibrous, odorless solids. The magnesium-rich end member of the cummingtonite-grunerite series is colorless and non-pleochroic, but the pleochroism increases with Fe/ Mg ratio. i. Grunerite Crystallography: Axial Ratios: a:b:c =0.5252:1:0.2925 : Cell Dimensions: a = 9.57, b = 18.22, c = 5.33, Z = 2; beta = 102.1° V = 908.72 Den(Calc)= 3.66 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. The colour is caused by the dominant iron rich grunerite, with quartz, and reddish brown iron rich riebeckite. The luster is glassy to pearly with colors ranging from green, brown to dark grey. Aspect ratio typically >10:1. It is often referred to as “brown Asbestos” because of its color. Cummingtonite is the name of a series as well as the name of a mineral. The mineral cummingtonite, is basically the middle member of the Cummingtonite Series, which include the minerals grunerite and magnesiocummingtonite. “Amosite” is derived from the term “AMOSA”, a shortened form of Asbestos Mines of South Africa (Ross et al., 1984). Amosite is characterized by its straight brittle fibers and utilized for cement sheeting and pipe insulation. Blue and pale blue colors indicate the cummingtonite form of amosite, and gold and blue colors indicate the grunerite form of amosite. Grunerite is a mineral of the amphibole group of minerals with formula Fe 7 Si 8 O 22 2.It is the iron endmember of the grunerite-cummingtonite series.It forms as fibrous, columnar or massive aggregates of crystals. In its natural state, amosite is known as grunerite, and it was mainly mined in South Africa. Asbestos, Amosite (CAS NO.12172-73-5) was discovered in 1853 and named for Louis Gruner, a Swiss-French chemist who first analysed it. Amosite. • Some confusion has arisen over the definition of amphibole asbestos which has amphiboles, for example grunerite (amosite), riebeckite (crocidolite), tremolite, actinolite and anthophyllite may occasionally occur in asbestos forms although these are rare in comparison to the normal varieties. The crystals are monoclinic prismatic.