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e Z3 Table 2. Descriptive term~ used by mineralogists to distinguish between asbestos and other types of fibrous textures. (Frequently in conjunction with fibrous.) Page number of an example is given. Werner (Friesleben) asbestartich Naumann [50, p. 324] asbestartig [66, p. 107 Naumann (Zirkel) Asbestform HaDy [30] no distinction [51, p. 707] Hoffmann (Breithaupt) asbestartig Nicol [52, p. 152] asbestiform [33, 2b, p. 306] Tschermak [62, p. 444] ? feinfaserig Jameson [36, II, p. 22] asbestous Groth [29, p. 151] asbestartig Phillips (Allan) asbestiform [54, p. 58] E. S. Dana [16, p. 384 asbestiform Thomson [61, I, p. 481] asbestiform Hintze [31, II, p. 1195] ? feinfaserig Mohs (Haidinger) asbestous Klockmann [41, p. 567] ? feinfaserig [49, II, 27] Doelter [21, II, p. 589] asbestartia Beudant [4, p. 387] asbestoide Rogers [58] no distinction Brard [7, p. 206] filamenteux Ford [24, p. 578] asbestos-like Bium [5, p. 242] ? feinfaserig Hurlbut [35, p. 446] asbestiform Rammelsberg [56, p. 358] asbestartig Kraus, Hunt, Ramsdell asbestiform Schmidt [60, p. 358] asbestartig [43, P. 392] Bristow [9, p. 85] asbestiform Berry, Mason asbestiform [3, P. 527] Cloizeaux [13, p. 81] asbestiforme Deer, Howie, Zussman asbestiform J. D. Dana [17, p. 153] asbestiform [18, II, P. 2431 a French: fibreux; German: faserig. The term fiber, in reference to asbestiform fibers, was equivalent to the concept of organic fibers because the early natural historians believed that asbestos was actually a vegetable. Mineralogists from the 18th century on did not specifically state that the term fiber is used because of its resemblance with organic fiber. However, that reasoning is apparent in their description of asbestos fibers as hair-like or capillary or thread-like, and in the types of names they have given to asbestos minerals, such as mineral-wood, rock- cotton, mountain cork, rock-wood. Jones [38] provided extensive details in the description of the similarity between asbestos and organic fibers (fig. 5) and concluded [38, p. 221] that: "The nature of the asbestos fibre is thus so far identical in structures with the organic fibres." - 11 N 0 a w 0 A 00 M+ W

C;w Fg. 1. Bibrv of 9hoo '* p WaaL Magti@°d Fig. 2. Filnmenh B00 of Naw Cattan. di.mchn. No. 1.-TLOtfmd On. Fig. 5. 8pun Ghw. Nn. 7. 13etfo~d O». Figure 5. Jones' [38] comparison of asbestos and organic fibers. Although the use of the term fiber has not been restricted to asbestos and included a number of other minerals they all had some characteristics reminiscent of organic fibers. In any case, the term fiber has never been used as a description of the elongated shape of crystals. For that acicular is the proper mineralogical expression. The term asbestos was first a species name, as noted earlier it was introduced by Werner and his school. Later it became a collective term, like c1Tys or gems, in reference to asbestiform varieties of a number of otherwise unrelated minerals. Parallel with the mineralogical terminology asbestos also became an industrial term for a category of mineral products containing asbestiform varieties of silicates. However, some commercial asbestos may be mixed with non-asbestiform acicular crystals or cleavage fragments. The quality of asbestos is related to: (a) the extent of the development of the preferred asbestos character (high tensile strength, flexibility, length of fibers) of the asbestiform fibers, and (b) the percentage of the less desirable non-asbestiform, acicular crystals or cleavage fragments present in the product. That is, the mineralogical and industrial definitions of asbestos are not fully coincident. The unusual properties of the asbestiform fibers were always recognized by the early users of asbestos as well as by mineralogists. These properties included high tensile strength [for example, 32,33,38,64], increased flexibility (noticed by all mineralogists), unexpected optical properties [for example, 53,69] and differences in surface properties, like surface charges [for example, 28,42,45,72]. VO Fig. 3. Fig. 4. Fibro of p,adint'Chro.d of HsvSilk Gmden Spid.. . 12

.4 With the introduction of high-power electron microscopy, a new tool for mineralogical research and a new area of applied mineralogy was established. Electron microscopes permitted the examination of extremely small mineral particles and the study of the fiber of fibril structures of various asbestiform crystals. The long suspected cylindrical (tubular, scroll-like) structure of the chrysotile fibrils [68] was directly observed by Maser et al. in 1960 [48] and a more detailed record was offered by Yada [70]. In addition to th`e cylindrical fibril structure, Cressey and Zussman [14] reported on a polygonal chrysotile structure which appears to be the dominating fibril structure in the so called "schweizerite" and "Provlen-type" chrysotile varieties. Comparable work, although with less spectacular results, was done on asbestiform amphiboles by several investigators, for example, Chisholm [12], Franco, Hutchinson, Jefferson, and Thomas [25]. The asbestiform amphibole fibril structure appears to be more subtle than that of chrysotile. The increased tensile strength and flexibility may be due to the presence of systematic defects such as faults, dislocations and twinning, and/or to the lack of surface defects. Of course, we know that defects can interfere with the cleavage and fracture of solids and are frequently introduced artifically in alloys and other crystals to enhance their strength as it is elaborated on in the textbook of Kelly and Nicholson [39]. Undoubtedly, time and extensive research will be needed before the structural causes of the unusual properties of asbesti- form amphiboles will be fully explained. Conclusions Several conclusions can be drawn from this review of the history of asbestos-related mineralogical terminology and its current misuse in environmental sciences: (1) Terms such as fiber, fibrous, asbestiform, and asbestos, have distinct meanings in mineralogy whether or not we can offer a complete crystal structural explanation for the development of the properties, reflected by these terms. (2) The asbestos-related mineralogical terminology is adequate and clear, and is not in need of revision. However, its full understanding requires a relatively comprehensive knowledge of mineralogy. Consequently, a set of detailed and unambiguous definitions should be prepared for inter- disciplinary use. (3) The asbestos-related mineralogical terms have been grossly misinterpreted in most of the recent literature of environmental sciences. The implied definitions are inadequate for the description and discussion of the crystal chemical and crystal physical properties of minerals, and endanger the success of coordinated, interdisciplinary studies aimed at the understanding and the solution of the health hazards created by asbestos pollution. The presence of any forei n particle in air and waters in excessive quantities is undesirable and is potentially harmful. It is imperative that all efforts be made to clean up the environment starting with one of the most dangerous mineral pollutants: asbestos. This job requires extensive interdisciplinary cooperation and the establishment of an unambiguous interdisciplinary language. The extensive list of definitions offered in the recent U.S. Bureau of Mines Information Circular [10] are comprehensive and consistent with mineralogical traditions. The adoptation of these definitions for the interdisciplinary language of asbestos studies should be considered. The following definitions of the four most critical asbestos-related mineralogical terms are based on their historical review. 13 0 w ~ 0 A Go ,.r U

FIBER An acicular single crystal, or a similarly elongated polycrystalline aggregate, which displays some resemblance to organic fibers. Examples for criteria of "resemblance to organic fibers" are: circular cross section, `flexibility, silky surface luster, axial lineation, threaded appearance, etc. Most of these fiber characteristics cannot be observed at electron-microscopic scale. Consequently, any elongated particle may be called a fiber (when fiber used as a shape-descriptive expression) provided that it displays parallel edges and apparently equidimensional cross section. That is, elongated triangular-shaped or irregular particles cannot be considered to have the shape of a fiber. FIBROUS The descriptive term used for a mineral which is composed of parallel, radiating or interlaced aggre9ates offbers, from which the fibers are usually separable. That is, the crystalline aggregate may be referred to as fibrous even if it is not composed of separable fibers, but has that distinct appearance. ASBESTIFORM A special type of fibrous habit in which the fibers are separable, and are more flexible and osp sess higher tensi~ strength than crystals in other habits of the same mineral. Increased flexibility and higher tensile strength are, apparently, the most distinct qualities of asbestiform fibers. These properties are undoubtedly due to certain structural variations and can justifiably be included in the definition. ASBESTOS A collective mineralo ical term which includes the asbestiform varieties of various si icate minerals. lT•T$ - The justification for restricting asbestos to silicate minerals may be questionable from the mineralogical point of view, as non-silicate minerals may also crystallize in fibrous habit and the fibers may possess asbestiform properties. However, these properties are expected to be different in magnitude from those of the asbestiform silicates and, therefore, from the health study's point of view, are justifiably excluded from the category of asbestos. The dl nt of fibrous habits must be due to certain unusual conditions which existed at the time of the mineral's crystallization. These conditions may be accompanied by structural modifications and by consequent changes in the mineral's physical properties. These changes, however, are usually not as conspicuous as they are in silicate asbesti- form fibers. In fibrous gypsum, for example, the only readily observable change is in the mineral's fracture pattern. The usually absent ((111)) cleavage plane is perfect in fibrous gypsum and is responsible for its acicular rather than platy fragments. This change in the cleavage pattern is probably due to some structural modification. On the other hand, the conditions of crystallizations may be such that no change in the mineral's structure and properties is necessary. For example, if a fibrous mineral is altered to another, the new mineral may show pseudomorphic fibrous appearance. Dana [16, p. 678] believes that the appearance of fibrous talc is due to its alteration from enstatite. laThe industrial quality of asbestos depends, in part, on the degree of development of the asbestiform fiber structure in the mineral. That is, if more crystals have the scroll- like structure in chrysotile, or the crystals have higher density of defects or twinning in asbestiform amphiboles or have fewer surface defects, the asbestiform fibers are stronger and more flexible, and thus they are more desirable. A similar relationship may exist between the degree of development and the density of asbestiform fibers in the bundles, and their biological activity. That is, the gradation of asbestiform development in a mineral, from acicular cleavage fragments to asbestiform fibers, may constitute dif- ferent health hazards. , 14

The critical reviews offered by Drs. Edwin Roedder and James H. Stout are acknowledged with appreciation. This study was in part supported by a grant from the Regional Copper- nickel Study, Environmental Quality Council, Minnesota. References [1] Agricola, Georgius (Bauer), De Natura Fossilium, (Basilea, 1546). [2] Amosite discredited, Am. Mineral. 34, 339 (1946). [3] Berry, L. G. and Mason, Brian, Mineralogy, (Freeman and Co., San Francisco, 1959). [4] Beudant, F. S. , Traite Elementaire de Mineralogie, (Verdipre, Paris, 1824). [5] Blum, J. R. , Lehrbuch der Oryktognosie, (G. Schweizerbart, Stuttgart, 1833). [6] Boot, Anselmus Boetius, de, Gemmarum et Lapidum Historia, (Lugduni Bataborum, 1647). [7] Brard, C. P., Nouveau elemens de Mineralogie, 2e ed., (Meguinon-Marvis, Paris, 1824). [8] Bradt, R. C., Newnham, R. E. , and Biggers, J. V., The toughness of jade, Am. Mineral. 58, 727-732 (1973). [9] Bristow, H. W. , Glossary of Mineralogy, (Longman et al. , London, 1861). [10] Campbell, W. J., Blake, R. L., Brown, L. L., Cather, E. E., and Sjoberg, J. J., Selected silicate minerals and their asbestiform varieties; mineralogical definitionand identification-characterization, (U.S. Bureau of M nes. Int. Circ. No. 8751, 1977). [11] Champness, P. E., Lorimer, G. W., and Zussman, J., Fibrous cummingtonite in Lake Superior: Discussion, Canad. Mineral, 14, 394 (1976). [12] Chisholm, J. E., Planar defects in fibrous amphiboles, J. Material Sci. 8, 475-483 (1973). [13] Cloizeaux, A., des Manuel de Min€ralogie, 2 vols., (Dunond, Paris. 1862). [14] Cressey, B. A. and Zussman, J. , Electron microscopic studies of serpentinites, Canad. Mineral. 14, 307-313 (1976). , [15] Cronstedt, A. F., FBrsoktill en Mineralogie, eller Mineral Rikets Uppstdlning, (Stockholm, 1758). [16] Dana, Edward S., The System of Mineralogy of James Dwight Dana, Descriptive Mineralogy, 6th ed.,(J- . Wiley and Sons, New York, 1914)-. [17] Dana, James D., Manual of Mineralogy, (Henry H. Peck, New Haven, 1857, new ed. (1871). [18] Deer, W. A., Howie, R. A., and Zussman, J., Rock-Forming Minerals, 5 vols., (J. Wiley and Sons, 1962, 1963). [19] Delasse, A., (analysis of crocidolite) Compt. Rend. 44, 766 (1847). _ [20] Dioscorides, P., IIepl vans 1ezplKns (Materia Medica), (Approx. 50 A.D.). [21] Doelter, C., Handbuch des Mineralchemie, 3 vols., (T. Steinkopff, Dresden and Leipzig, 1912, 1914, 1918). [22] Drysdall, A. R. and Newton, A. R., Blue asbestos from Northern Rhodesia and its bearing on the genesis and classification of this type of asbestos, Am. Mineral. 45, 53-59 (1960). 15 2063104817

[23] Engleston, T., A Catalogue of Minerals and 5 ny onyms, (J. Wiley and Sons, New York, 1892). [24] Ford, W. E. , Dana's Textbook of Mineralogy, 4th ed., (J. Wiley and Sons, New York, 1951). [25] Franco, M. A., Hutchinson, J. L., Jefferson, 0. A., and Thomas, J. R., Structural imperfection and morphology of crocidolite (blue asbestos), Nature 266, 520-521 (1977). [26] Freiesleben, J. C., A. G. Werner's Letztes Mineral-System, (Craz and Gerold, Freyberg and Wien, 1817). [27] Gary, M. , McAfee, R. , Jr., and Wolf, C. L. , (editors), Glossary of Geology, (Am. Geol. Inst., Washington, D. C., 1972). [28] Great Lakes Research Advisory Board, Asbestos in the Great Lakes Basin, (February, 1975). [29] Groth, P., Tabellarische Ubersicht des Mineralien, 4te Aufl., (Friedrich Vieweg und Sohn, Braunschwe g, 1898 . [30] HaOy, M. L'Abbe, Traitd de Mineralogie, 5 vols., (Bachelier, Paris, 1801, 2e edition, 1822). [31] Hintze, C., Handbuch der Mineralogy, Bd. 2, (Von Veit, Leipzig, 1897). [32] Hodgson, A. A., Fibrous silicates, Lect. Ser. 1965 No. 4, (The Royal Inst. of Chem., 1966). [33] Hoffmann, C. A. S., Handbuch der Mineral6 ie, (after Bd. 2a by A. Breithaupt), 4 vals., (Craz and Gerold, Freyberg, 1811-1818 . [34] Hoffmann, C. A. S., (about Werner's Mineral System), 17th ed., 80rgm. 369 (1789). [35] Hurlbut, C. S., Jr., Dana's Manual of Mineralogy, (J. Wiley and Sons, New York, 1959). [36] Jameson, Robert, System of Mineralogv, (Archibald Constable, Edinburgh, 1816). [37] Jameson, Robert, Manual of Mineralogv, (Archibald Constable, Edinburgh, 1821). (38] Jones, R. H., Asbestos, its Properties, Occurrence and Uses, (Crosby Lockwood, London, 1890). [39] Kelly, A. and Nicholson, R. B., Strengthening Methods in Crystals, (Appl. Sci. Publ., London, 1971). [40] Kenngott, Adolf, Das Mohs'sche Mineral System, (C. Gerold, Wein, 1853). [41] Klockmann, F., Lehrbuch der Mineralogie, (F. Enke, Stuttgart, 1903). [42] Kramer, J. R. , Fibrous cuamingtonite in Lake Superior, Canad. Mineral. 14, 91-98 (1976). (43] Kraus, E. D., Hunt, W. F., and Ramsdell, L. S., Mineralogy, (McGraw-Hill, New York, 1959). [44] Kryvial, R. J., Wood, R. A., and Barrett, R. E., Identification and assessment of asbestos emissions from incidental sources of asbes os, (U.S. Eriv. Prot. Agency,: €PKTbT2-7 -iT,-WasTingtonep't. 19T4j- [45] Langer, A. M., Approaches and constraints to identification and quantitation of asbestos fibers, env. Health Presp. 9, 133-136 (1974). 16

Cia [46] Light, W. G. and Wei, E. T., Surface charge and asbestos toxicity, Nature 265, 537- 539 (1977). [47) Linneaus, C. A., 5 sy tema Naturae, (Holm, 1768). [48] ~Maser, M., Rice, R. V., and Mug, H. P., Chrysotile morphology, Am. Mineral. 45, 680-688 (1960). [49] Mohs, Frederich, GrUndriss der Mineralogie, 2 vols., (Dresden, 1822). English: Treatise on Mineralogy, Transl. by W. Haidinger, 2 vols., (Hurst and Robinson, London, 1825 . ' [50] Naumann, Carl F., Elemente der Mineralogie, 8te Aufl., (W. Engelmann, 1871). [51] Naumann, Carl F., Eiemente der Mineralogie, 13te Aufi. by Ferdinand Zirkel, (W. Engelmann, 1898). [52] Nicol, James, Elements of Mineralogy, (A. and C. Black, Edinburgh, 1873). [53] Peacock, M. A. , The nature and origin of the amphibole asbestos of South Africa, Am. Mineral. 13, 241-285 (1928). [54] Phillips, William, An Elementary Introduction to Mineralogy (1823), 4th ed. by R. Allan, (Longman, et al., London, 1837). [55] Plinius Secundus, C., Historia Naturalis, 27 books (77 A.D.) [56] Rammelsberg, C. F., Worterbuch des Chemischen Theils der Mineralogie, (C. G. Luderitz, Berlin, 1841). (57] Rammelsberg, C. F. , J. J. Berzelius' Neues Chemisches Mineral System (J. L. Schrag, NUrnberg, 1847). [58] Rogers, A. F. , Introduction to the Study of Minerals, (McGraw-Hill, New York 1937). [59] Scheerer, Th., (analysis of byssolite) POgg. Ann. 84, 389 (1851). [60] Schmidt, F. A., Mineralienbuch, (Krais and Hoffman, Stuttgart, 1855). [61] Thomson, Thomas, Outline of Mineralogy, Geology, and Mineral Analysis, 2 vols., (Baldwin and Cradock, London, 1836). [62] Tschermak, Gustav, Lehrbuch der Mineralogie, (Alfred Holder, Wein, 1884). [63] U.S. District Court, District of Minnesota, 5th Division, Supplemental Memorandum, (No. 5-72, Civil 19, Appendix 5, Judge Miles Lord, May 11, 1974). [64] Vermaas, F. H. 5., The amphibole asbestos of South Africa, Trans. Proc. Geol. Soc. South Africa 55, 199-229 (1952). [65] Walerius,I. A., Mineral-riket, (Hotm, 1847). [66] Werner, A. F. , Ausserlichen Kennzeichen des Fossilien, (Leipzig, 1774), English: On the external character ransl A. V. Carozzi (U of I11.. Press, 1962). [67] Whittaker, E. J. W., The structure of Bolivian crocidolite, Acta Crystallogr. 2, 312- 317 (1949). [68] Whittaker, E. J. W., The structure of chrysotile, Acta Crystallogr, 6, 747 (1953). [69] Wylie, A., Optical properties of asbestiform amphiboles and their non-asbestiform analogues, U.S. Bureau of Mines, I.R. (in press). 17 2063104819

C7 [70] Yada, Keiji, Study of chrysotile asbestos by a high resolution electron microscope, Acta Crystallogr. 23, 704-707 (1967). [71] Zoltai, T. and Stout, J. H., Comments on asbestiform and fibrous mineral fragments (Minn. Poll. Contr. Agency, 1935 W. Co. Road B-2, Roseville, MN 55113, 1976). [72] Zoltai, T., Veres, I., Wagner, M. J., and Hammer, R. F., Surface charges of asbestiform amphibole fibers, (in manuscript). Discussion M. COSSETTE: Could you tell me if the use of the word asbestoid implies that it is not quite asbestos? T. ZOLTAI: Brard and Beudant used it in lieu of asbestartich or asbestiform, that is, the expression is equivalent to asbestiform. A. BOHMER: Are you suggesting that if a mineral has an asbestiform habit in its varieties and it has a three-to-one ratio it is asbestos? That is, should we limit our classification of asbestiform to those minerals? ZOLTAI: Yes. 18