Nomenclature Of Minerals Research Articles

Crystal Structures of Natural Zeolites

### General aspects According to the recommended nomenclature for zeolite minerals (Coombs et al. 1998), there are more than eighty distinct zeolite species. Table 1⇓ (see Appendix below) is a listing of the zeolite minerals discussed in this chapter. Although zeolites are not as geologically abundant or widespread as many other silicate mineral groups, there is perhaps more interest in the crystal structures of zeolites than in any other mineral group, as evidenced by the number of reported crystal structure refinements (Table 2⇓). View this table: Table 1. Alphabetical list of zeolites and zeolite-like minerals covered in this chapter with their, chemical formulas, space group, cell parameters, channel description, and FD (T/1,000A3). (Channel descriptions from Meier et al. (1996); cell parameters and chemical formulas from Gottardi and Galli 1985; and new data taken from this chapter.) Meier at al. (1996) use the following symbols for channel descriptions: bold numbers represent the number of tetrahedra defining the channel, the channel free diameter is given in A, the number of stars represent the number of channels in a given direction, the connectivity of channels is given by “|” to represent connected channels or “⇔“ to represent non-connected channels. View this table: Table 2. Number of crystal structures reported in ICSD (1995) for selected mineral groups. Oxygen and silicon are the two most abundant elements in the Earth’s crust, followed by Al, Fe, Ca, Na, Mg, K. Along with H, Ba, and Sr, these are also the major elements found in most zeolite minerals. In fact, many similarities can be drawn between the feldspars, the most abundant mineral group in the Earth’s crust, and zeolites. The two most important principles in understanding zeolites (or any mineral group) are that charge balance must be maintained (i.e. the sum of the formal valence charges of the ions in the chemical formula must …

Proposed nomenclature for samarskite-group minerals: new data on ishikawaite and calciosamarskite

AbstractThe current definition of samarskite-group minerals suggests that ishikawaite is a uranium rich variety of samarskite whereas calciosamarskite is a calcium rich variety of samarskite. Because these minerals are chemically complex, usually completely metamict, and pervasively altered, their crystal chemistry and structure are poorly understood. Warner and Ewing (1993) proposed that samarskite is anA3+B5+O4mineral with an atomic arrangement related to α-PbO2. X-ray diffraction analyses of the recrystallized type specimen of ishikawaite and the Ca-rich samarskite reveal that they have the same structure as samarskite-(Y) recrystallized at high temperatures. Electron microprobe analyses show that the only significant difference between samarskite-(Y), ishikawaite, and calciosamarskite lies in the occupancy of theA-site. TheA-site of samarskite-(Y) is dominated by Y+REEwhereas theA-site of ishikawaite is dominantly U+Th and calciosamarskite is dominantly Ca. Additionally, a comparison of these data to those of Warner and Ewing (1993) show that in several cases Fe2+or Fe3+are dominant in theA-site. We propose that the name samarskite-(REE+Y) should be used when one of these elements is dominant and that the mineral be named with the most abundant of these elements as a suffix. The name ishikawaite should be used only when U+Th are dominant and the name calciosamarskite should only be used when Ca is the dominant cation at theA-site. Finally, because of the inability to quantify the valence state of iron in these minerals, the exact nature of the valence state of iron in these minerals could not be determined in this study.

Recommended nomenclature for zeolite minerals: report of the subcommittee on zeolites of the International Mineralogical Association, Commission on New Minerals and Mineral Names

AbstractThis report embodies recommendations on zeolite nomenclature approved by the International Mineralogical Association Commission on New Minerals and Mineral Names. In a working definition of a zeolite mineral used for this review, interrupted tetrahedral framework structures are accepted where other zeolitic properties prevail, and complete substitution by elements other than Si and Al is allowed. Separate species are recognized in topologically distinctive compositional series in which different extra-framework cations are the most abundant in atomic proportions. To name these, the appropriate chemical symbol is attached by a hyphen to the series name as a suffix except for the names harmotome, pollucite and wairakite in the phillipsite and analcime series. Differences in spacegroup symmetry and in order—disorder relationships in zeolites having the same topologically distinctive framework do not in general provide adequate grounds for recognition of separate species. Zeolite species are not to be distinguished solely on Si : Al ratio except for heulandite (Si : Al < 4.0) and clinoptilolite (Si : Al ⩾ 4.0). Dehydration, partial hydration, and over-hydration are not sufficient grounds for the recognition of separate species of zeolites. Use of the term ‘ideal formula’ should be avoided in referring to a simplified or averaged formula of a zeolite.Newly recognized species in compositional series are as follows: brewsterite-Sr, -Ba; chabazite-Ca, - Na, -K; clinoptilolite-K, -Na, -Ca; dachiardite-Ca, -Na; erionite-Na, -K, -Ca; faujasite-Na, -Ca, -Mg; ferrierite-Mg, -K, -Na; gmelinite-Na, -Ca, -K; heulandite-Ca, -Na, -K, -Sr; levyne-Ca, -Na; paulingite-K, -Ca; phillipsite-Na, -Ca, -K; stilbite-Ca, -Na.Key references, type locality, origin of name, chemical data, IZA structure-type symbols, space-group symmetry, unit-cell dimensions, and comments on structure are listed for 13 compositional series, 82 accepted zeolite mineral species, and three of doubtful status. Herschelite, leonhardite, svetlozarite, and wellsite are discredited as mineral species names. Obsolete and discredited names are listed.

Recommended nomenclature for zeolite minerals: Report of the Subcommittee on Zeolites of the International Mineralogical Association, Commission on New Minerals and Mineral Names

This report embodies recommendations on zeolite nomenclature approved by the International Mineralogical Association Commission on New Minerals and Mineral Names. In a working definition of a zeolite mineral used for this review, interrupted tetrahedral framework structures are accepted where other zeolitic properties prevail, and complete substitution by elements other than Si and Al is allowed. Separate species are recognized in topologically distinctive compositional series in which different extra-framework cations are the most abundant in atomic proportions. To name these, the appropriate chemical symbol is attached by a hyphen to the series name as a suffix except for the names harmotome. pollucite and wairakite in the phillipsite and analcime series. Differences in space-group symmetry and in order-disorder relationships in zeolites having the same topologically distinctive framework do not in general provide adequate grounds for recognition of separate species. Zeolite species are not to be distinguished solely on Si:Al ratio except for heulandite (Si:Al or =4.0). Dehydration, partial hydration, and over-hydration are not sufficient grounds for the recognition of separate species of zeolites. Use of the term ideal should be avoided in referring to a simplified or averaged formula of a zeolite. Newly recognized species in compositional series are as follows: brewsterite-Sr, -Ba: chabazite-Ca, -Na, -K; clinoptilolite-K, -Na, -Ca; dachiardite-Ca, -Na; erionite-Na, -K, -Ca: faujasite-Na, -Ca, -Mg; ferrierite-Mg, -K, -Na; gmelinite-Na, -Ca, -K; heulandite-Ca, -Na, -K, -Sr; levyne-Ca, -Na; paulingite-K, -Ca; phillipsite-Na, -Ca, -K; stilbite-Ca, -Na. Key references, type locality, origin of name, chemical data, IZA structure-type symbols, space-group symmetry, unit-cell dimensions, and comments on structure are listed for 13 compositional series. 82 accepted zeolite mineral species, and three of doubtful status. Herschelite, leonhardite, svetlozarite, and wellsite are discredited as mineral species names. Obsolete and discredited names are listed.

Mineral nomenclature: zirconolite

AbstractThe nomenclature of CaZrTi2O7 minerals has become very confused, such that zirconolite, zirkelite and polymignite each have acquired multiple meanings and represent five different crystal structures. To resolve these inconsistencies, the IMA approved resolutions as follows. Zirconolite is the non- crystalline (metamict) mineral or mineral with undetermined polytypoid of CaZrTi2O7. Zirconolite-3O is the three-layered orthorhombic polytypoid of CaZrTi2O7. Zirconolite-3T is the three-layered trigonal polytypoid of CaZrTi2O7. Zirconolite-2M is the two-layered monoclinic polytypoid of CaZrTi2O7. Polymignite (metamict) is discarded as equivalent to zirconolite. Zirkelite is the cubic mineral with formula (Ti,Ca,Zr)O2−x.

Discussions and Recommendations Concerning the Nomenclature of Clay Minerals and Related Phyllosilicates

AbstractAttempts to find a generally acceptable scheme of classification and nomenclature for clay minerals by the nomenclature committees of The Clay Minerals Society (C.M.S.), the Comité International pour l’Étude des Argiles (C.I.P.E.A.), and the International Mineralogical Association (I.M.A.) are summarized. The C.M.S. committee has been working on this problem continuously since 1961 and has transmitted its views to C.I.P.E.A., first at the time of the Stockholm meeting, 1963, and subsequently, in more detail, after receiving the first draft of the C.I.P.E.A. proposals. The C.I.P.E.A. committee held discussions in Stockholm, 1963, and subsequently submitted a first draft to 32 nations; from the replies received, a final draft of the C.I.P.E.A. proposals was prepared and submitted to the I.M.A. in 1964. The report from the I.M.A. was made available in August, 1965.

Clay mineralogy

The development of clay mineralogy is traced from earliest times and the difficulties encountered in dealing with clay minerals discussed. After consideration of current concepts concerning the structure, nomenclature, classification and origin of clay minerals, the methods of investigation likely to be of use are outlined and critically assessed. The nature and properties of each group of clay minerals are described in the light of recent research, and attention is also given to non-crystalline and accessory minerals. Many of the problems still awaiting solution are outlined.

The Classification and Nomenclature of Clay Minerals

A report is given of the decisions reached at a meeting on the classification and nomenclature of clay minerals held under the auspices of Comite International pour l’Etude des Argiles at Brussels in July 1958. Tables of recently-proposed classification systems are included and some comments made on problems requiring agreement.

Report of the Clay Minerals Group Sub-Committee on Nomenclature of Clay Minerals

This sub-committee consisting of Mr G. Brown (Chairman), Dr M. H. Hey, Dr D. M. C. MacEwan and Dr R. C. Mackenzie was asked to make proposals for the nomenclature of clay minerals and these proposals were presented in part at a C.I.P.E.A. meeting in Paris in July, 1954, where some useful discussion ensued. The outcome of that meeting was a suggestion that the proposals be published more fully. It is important to remember that these are proposals for consideration and not a set of rules. The Clay Minerals Group would welcome comments on these proposals (adverse or otherwise) or the comments may equally well be sent to C.I.P.E.A. Addresses to which comments, suggestions, criticisms, etc., should be sent are : For the Clay Minerals Group : Mr G. Brown, Pedology Department, Rothamsted Experimental Stn., Harpenden, Herts., England. For C.I.P.E.A. : Dr W. F. Bradley, Illinois State Geological Survey, Urbana, Illinois, U.S.A.

Some Hydrous Micas in South African Clays and Shales

At the 4th International Soil Science Congress held in Amsterdam (1950) a special meeting discussed the nomenclature of clay minerals and suggested “hydrous mica” as a general term for those clay minerals that are neither well crystallised micas nor pure expanding minerals.In the past various names have been used for the hydrous micas. As early as 1912, Galpin, and later, in 1920, Bayley, introduced the terms “hydro-mica” and “hydrous mica” respectively, to designate a micaceous clay mineral. Since then, reports have been made of the presence in soils of a potash-bearing clay mineral (Wherry et al., 1929), and in clays of a mica-like clay mineral (glimmerartige Tonmineralien) (Endell et al., 1935), and a sericite-like mineral (Grim, 1935). In 1937 Grim et al., for the first time proposed the term “illite” as a “general term for the clay mineral constitutents of argillaceous sediments belonging to the mica group.” Other names include bravaisite (Ross and Hendricks) and sarospatite (Maegdefrau and Hofmann, 1937), but the validity of these as specific minerals is questionable since they have been found to exist as mixtures of hydrous micas and montmorillonoids (Bradley, 1945; Brindley, 1951).

International agreement in mineralogical and crystallographical nomenclature

A Committee on Nomenclature and Classification of Minerals was appointed at the first annual meeting of the Mineralogical Society of America in December 1920, and two of its reports have been recently issued in the ‘American Mineralogist’. Such a committee for standardizing nomenclature is clearly needed, but it must take a far wider view. If the recommendations can be, or are likely to be, adopted only in their country of origin then the result will be still further confusion in the nomenclature of the science. It is especially important in this connexion to bear in mind that science is world-wide, and its language should, as far as possible, be adapted to meet international needs. The tendency to adapt names to particular languages should rather be discouraged.

LXV. Scottish Geology: Its Proofs and Problems

T he author stated that by its proofs he meant what was known, or at least generally admitted, by competent geologists; and by its problems what was still doubtful and required further investigation. His object was not to sketch the history of Scottish Geology, which, about the beginning of the century, was a mass of theories and disputations between Wernerians and Huttonians, and which at a later period was little else than a nomenclature of rocks and minerals; but he could not avoid mentioning the names of such men as Hutton, Playfair, Ure, Sir James Hall, M‘Culloch, Williams, and Jamieson, as contributing largely, even amidst these unproductive discussions, to the progress of the science. Legitimate geology could date back little more than thirty years, and during that period its advancement in Scotland was indebted in no small degree to the labours of Fleming, Smith, Cunningham, M‘Laren, Hugh Miller, and especially to those of Lyell, Murchison, Nicol, Geikie, and others who were still steadily endeavouring to unravel its many complicated physical as well as palæontological problems. He then took in review the various stratified systems, from the Laurentian up to the most recent accumulations, pointing out the known from the unknown, and from the doubtful or what required more minute investigation. Admitting the existence of Laurentian strata in the Hebrides and northwest corner of Scotland, it still required investigation to determine whether these were the true equivalents of the rocks of the St. Laurence, or were merely a set of gneissic schists