Abstracts of New Mineral Species
by
Joseph A. Mandarino
E-mail: j.a.mandarino@sympatico.ca
Chairman Emeritus
Commission on New Minerals and Mineral Names (CNMMN)
of the International Mineralogical Association
and
Curator Emeritus
Department of Mineralogy, Royal Ontario Museum
100 Queen's Park, Toronto, Ontario M5S 2C6
INTRODUCTION
Shortly before I retired from my position as Chairman of the Commission on New Minerals and Mineral Names (CNMMN) of the International Mineralogical Association (a position I had held from January 1983 to December 1994) I approached Mineralogical Record editor Wendell Wilson to see if he would like to publish abstracts of new mineral descriptions. His reaction was positive, and the first abstracts appeared in the September-October 1996 issue of the magazine. Abstracts have appeared there periodically ever since. It was recently decided, however, that these abstracts could be presented more efficiently on the Mineralogical Record's newly remodeled website, leaving more room in the magazine for other features. Thus, from now on, they will appear here, in much more timely fashion than magazine publication and space allotments have previously allowed. And to give this online database of abstracts a good start, many of those already published will be included here as well.
The abstracts can be called up from either of the two drop-down menus above. The alphabetical menu (on the left) will be most useful when a particular species is being sought. The chronological listing (on the right) presents the species according to the year of publication (and then alphabetically within that year), so that the most recently added species can easily be found.
PRODUCTION OF THE ABSTRACTS
Many published mineral descriptions are relatively easy to abstract, but others pose various challenges. One of the amazing things I discovered while preparing abstracts for The Mineralogical Record is the tendency of some authors to omit certain data from their published descriptions, even though they had presented these data in their proposals to the CNMMN. Fortunately I had retained copies of all of the proposals voted upon during my tenure as Chairman, so it was easy to compare the data given in a published description with the data given in the proposal. I therefore decided to supplement my abstracts with missing data from the original proposals, so I added a statement which said: "Some of the data given in this abstract were taken from the original IMA proposal " Ultimately, this problem became such a common occurrence that it made more sense to drop this repetitive sentence from the abstracts. Instead, this statement will serve notice that most of the abstracts presented here contain some data from the original IMA proposals, with which the current Chairman has been kind enough to provide me. The added information does not include major numerical data, but includes such properties as streak, diaphaneity, tenacity, etc., which the authors simply neglected to mention.
But sins of omission are not the only ones I encountered; there are many instances of sins of commission as well. It rather surprised me to find how many calculation errors are present in published mineral descriptions. Most often, these involve miscalculation of density and subscripts of the empirical formula. Using the chemical analytical data and the unit cell parameters given by the authors in their descriptions, I have recalculated the density and the subscripts of the empirical formulas. In general, I calculate empirical formulae of non-sulfide/sulfosalt minerals on the basis of the number of anions (i.e., oxygen, fluorine, chlorine, hydroxyl, etc.) plus water. The formulae of sulfides and sulfosalt minerals are calculated on the basis of the total number of atoms. Calculations of the density were carried out wherever possible, using the chemical analytical data and unit cell parameters. Other checks which I have carried out include calculations for the optical data of biaxial minerals to ensure that the relationship between the three principal indices of refraction and 2V is valid. The results of my calculations often point out errors in the papers.
Where my calculated values differ from those given by the authors, I have used my values in the abstracts. The reader may well ask why I put my calculations above those of the authors. My defense is one I used often during my tenure as chairman of the CNMMN; atomic weights of elements and straightforward arithmetic are not dependent upon latitude and longitude. In other words, if I use an author's data and calculate something based on a universally accepted mathematical equation and constants, the answer arrived at in Toronto should be correct. I hasten to add that I do not put all the blame for published miscalculations on the authors; after all, to err is human, and we all benefit from the services of editors and reviewers. However, the fact that the referees and editors who reviewed the papers failed to catch some errors proves that they are human also. Before any editors claim that errors do not occur in their journals, let me assure them that no journal used in the production of these abstracts is consistently error-free.
It is disappointing that very few new mineral descriptions include crystal drawings. This happens even in cases where the authors give a list of observed crystal forms as well as a brief description of the habit, a photograph or an SEM image. This is totally unacceptable now that crystal drawing programs such as SHAPE are available. Wherever possible, I have used the data given in a paper to produce a crystal drawing. Where no drawing was supplied in the paper, I sent a copy of my drawing to the authors for their comments.
In those cases where a description does contain a crystal drawing, I have reproduced the drawing using SHAPE. Sometimes the results are quite startling because my drawing may bear little or no resemblance to the drawing in the paper! Most often, the problem is that the authors have used a non-standard orientation. Long ago, crystallographers and mineralogists realized that because of the many ways crystals can be oriented in drawings, a set of standard orientations had to be established. Departures from these standards add confusion to the literature. Some authors have used an orthographic instead of a clinographic projection in their descriptions. In such cases, I have given a clinographic projection in the abstract.
THE ABSTRACTS
Each abstract begins with the name of the mineral followed by the ideal chemical formula.
Locality
So far as possible, I have used the locality information given by the authors. In several cases, I have included additional information. It is surprising that some authors omit the names of provinces (or their equivalents) and, in relatively few cases, even the country. Some authors are precise enough to include the latitude and longitude of the locality. Even here, however, parochialism rears its ugly head and the reader is sometimes required to determine if the latitude is N or S and the longitude is E or W. In most cases this was not a problem, but when the given longitude is within a few degrees of the Greenwich line it helps to have E or W noted. There were times in our recent history when certain localities were hidden from the reader; hopefully, this is over and authors should make every effort to identify a locality in terms of latitude and longitude. There is great inconsistency in defining certain localities, even among the same authors describing different minerals from a single locality. In such cases, I have extracted the most detailed information and used this for all the minerals from the locality.
Occurrence
Wherever possible, I have tried to include the type of occurrence. This may be a rock type or a geological zone within a deposit. Under "Associated minerals," I have tried to include as many as the authors list, but this varies with the authors.
General Appearance
This is a very short statement about the mode of occurrence: grains, crystals, aggregates, etc. as well as sizes of the crystals and/or aggregates.
Physical Properties
In published mineral descriptions, the amount of physical data varies greatly. Many authors are content to give only "hard data," i.e., crystallographic parameters, structural data, and chemical analytical results. The so-called "soft data," those which we can observe or easily estimate, are often neglected in mineral descriptions. It is ironic that the latter properties are those which alerted the collector to bring an unknown mineral to a professional mineralogist for identification and, subsequently, for characterization as a new species. The following properties include both "hard" and "soft" data.
Luster: Usually, this is expressed as vitreous, adamantine or metallic. Other descriptive terms, such as greasy, pearly, resinous, etc. are also used. Unfortunately, many authors apply the term vitreous to minerals with optical data which prohibit this term. It is well established that a mineral with indices of refraction about 1.75 or higher has a luster which is best defined as adamantine or resinous.
Diaphaneity: This is usually defined as transparent, translucent or opaque, but transitions between two of these may exist; i.e., transparent to translucent or translucent to opaque.
Color: There is seldom a problem with this, although terms such as "wine-colored" or "honey-colored" are still commonly used in spite of the fact that there are many colors of wines and honey.
Streak: This property is often ignored by authors. When I received proposals for new minerals, the streak often was omitted with the statement that it could not be determined. It was somewhat embarrassing to point out that if the authors had produced an X-ray powder pattern they had used a powder and the powder's color is the streak. However, many authors still do not give this information. The importance of streak, as with other physical properties cannot be minimized.
Luminescence: This property may be quite specific for a mineral, but information in a description is often difficult to find.
Hardness: Usually, the Mohs hardness is given. In the case of metallic minerals, the micro-indentation value or Vickers Hardness Number (VHN) for a particular load is given with or without the Mohs value. One aspect of this property that should be avoided is the use of decimal values for Mohs hardness values. To state that a mineral has a hardness of 4.5 implies a much greater precision than is possible using the Mohs scale. In a case such as this, the hardness should be expressed as 4½ or, even better, between 4 and 5.
Tenacity: The usual descriptive terms are brittle, malleable, or sectile, but not all authors give this information even if it is noted in their IMA proposal.
Cleavage: The information on cleavage varies greatly. Ideally, for each cleavage, there should be a statement embodying the direction (expressed in Miller indices) and the degree of perfection. Angles between cleavages are useful, but seldom given.
Fracture: Again, information on this property often is missing.
Density: Two values should be expected: the measured density (or specific gravity) and the density calculated from the volume derived from the unit cell parameters, the formula weight, and the number of formula units per unit cell (expressed as Z). It is incredible how difficult it is to find the value of Z in some papers. Often, it is not in the text of the paper, but can be found in the paper's abstract. In other cases, it has to be derived from the data given in the paper.
Crystallography
This section starts with the crystal system: triclinic, monoclinic, orthorhombic, hexagonal, hexagonal (trigonal), tetragonal, or cubic. This is followed by the space group and the unit cell parameters. These parameters should include not only the values of the unit cell (a, b, c, α, β, γ), but the unit cell volume (V), Z, and the axial ratio (a:b:c for triclinic, monoclinic, and orthorhombic unit cells; c:a for hexagonal and tetragonal unit cells). With regard to morphology, crystallographic forms are commonly listed, but often not utilized (as noted above) to produce a crystal drawing. Twinning is also recorded here (if observed). It should be noted that the unit cell volume often is not listed in descriptions. Some people argue that the volume can be calculated if the cell parameters are known, so it need not be given. However, most of the unit cell parameters given in these abstracts are derived by least-squares refinement of the X-ray powder diffraction data. The same computer program that facilitates this calculation also derives the unit cell volume. Because this is a statistical process, the resulting unit cell volume is not equal to the volume calculated from the cell parameters. In effect, the product of 2 x 3 x 4 is not always 24; it may be 23.9 or 24.3! If the unit cell parameters derived by least squares refinement are used, it makes sense to use the unit cell volume derived by the same process.
X-ray powder diffraction data
Generally, I have tried to list the seven strongest lines in the X-ray powder diffraction pattern and the observed intensities. Depending on the data, however, this may vary between five and ten lines. Most authors use a numerical system for the observed intensities which designates the strongest line as 10 or 100, but a few authors prefer an alphabetical system with intensities noted as VS or vS for very strong, S for strong, MS or mS for medium strong, M for medium, W for weak, etc.
Optical data
The optical character (isotropic, uniaxial, or biaxial) is given. For the latter two, the sign (+ or -) is also given. This is followed by the principal indices of refraction (n for isotropic, ω and ε for uniaxial and α, β, γ for biaxial). For uniaxial crystals, the pleochroism is also noted. For biaxial crystals, 2V(meas.) and 2V(calc.) are given as well as dispersion of the optic axes, pleochroism, and orientation of the optical indicatrix. For metallic minerals and some nonmetallic minerals with high indices of refraction, data obtained in reflected light are given: color, anisotropism, bireflectance, and pleochroism. Reflectance values for the IMA/COM wavelengths (470 nm, 546 nm, 589 nm, and 650 nm) are given.
The complete optical characterization of many new minerals proves difficult. However, more intense effort on the part of authors could improve the completeness of optical data. It is apparent that many describers of new species are not well-trained in optical mineralogy. Misstatements about the optical sign are not uncommon. Some authors give information on the dispersion of uniaxial minerals; in optical mineralogy, dispersion usually refers to the dispersion of the optic axes and there can be no dispersion of a single optic axis, consequently dispersion only has meaning for biaxial minerals.
Chemical analytical data
The weight percentages determined by chemical analysis are listed. The analytical method is also noted. Finally, the empirical formula derived from the analytical data is given. As noted earlier, my calculations of subscript values are often quite different from those given by some authors. One common reason for this is that some authors base their calculations on the number of certain cations (for example, Si + Al), whereas I base my calculations on the number of anions. The reason is that a crystal structure is based on an anion (usually oxygen) framework into which the cations occupy interstitial spaces. The unit cell of a mineral should contain a number of oxygens equal to an integer such as 32; if a cation or group of cations is made equal to an integer, the result may be 32.47 oxygens in the unit cell.
Relationship to other species
Wherever possible, the relationship of the mineral to other species is noted, such as "membership" in a group.
Name
The derivation of the name is given.
Comments
This includes the original IMA number assigned when the proposal was submitted and any other comments pertinent to the mineral, such as deviations of data given here from those given in the reference. Details concerning the crystal drawings (if any) produced for the abstracts also appear here.
References
The entry for the reference includes the authors, year of publication, title of paper and full reference data (journal, volume, pages). In some cases, more than one paper is listed.
If the paper in which the journal is published is in a language other than English (or its close relatives, American, Canadian, Australian, etc.) the name of the journal is not translated. Exceptions to this are some of the Chinese journals which have English as well as Chinese names. The names of Russian journals are transliterated from the Cyrillic alphabet into the Latin alphabet and for this I have used the journal names listed in A. P. Khomyakov's book, Mineralogy of Hyperagpaitic Alkaline Rocks (1995), Oxford University Press. Original Russian titles of the papers have been translated into English, often by the journals themselves. One last note about Soviet/Russian journals. The names of two journals given in this book each have two names depending on the year of publication. Prior to 1992, these journals were called Zapiski Vsesoyuznogo mineralogicheskogo obshchestva and Doklady Akademia Nauk SSSR. Since 1992, their names are, respectively, Zapiski Vserossuskogo mineralogicheskogo obshchestva and Doklady Akademia Nauk.
A PLEA TO AUTHORS OF NEW MINERAL DESCRIPTIONS
Inasmuch as I will be continuing to produce these abstracts for the foreseeable future, it will assist me greatly if authors will ensure that the maximum amount of data is included in the published description. More important, is the obligation which each author owes to the reader of such descriptions to clearly present all of the pertinent data for the mineral being described.
It is not uncommon to search through the text of a paper without finding a certain set of data, only to find that it is listed in the paper's abstract. And there are also cases where the data given in the abstract do not match those given in the text of the paper. One outstanding example comes to mind. The calculated density of a new mineral was given as one value in the text and a quite different value in the abstract; to make matters worse, neither value was correct! Perhaps, editors and referees should take their responsibilities more seriously as well.
ACKNOWLEDGMENTS
I am pleased to acknowledge the assistance of the following people: Wendell E. Wilson (The Mineralogical Record); Andrew C. Roberts (Geological Survey of Canada), who supplied photocopies of many papers; Malcolm E. Back (Royal Ontario Museum), who assisted me in many ways; Margaret Coutinho and Harold Dales (Royal Ontario Museum), who spent many hours at a photocopier; B. Darko Sturman (Royal Ontario Museum), who helped me through some incredibly complex crystallographic problems; Prof. Andrei Bulakh (St. Petersburg University), who helped sort out some of the Soviet/Russian localities for me; Joan C. Mandarino, my wife, who listened patiently and sympathetically to my ravings about missing and erroneous data; the authors of many descriptions, who supplied me with reprints; and those authors who took enough pride in their work to produce complete descriptions-may their numbers increase.
TO THE READER
I trust that the information given in these abstracts is of use to you and I welcome any suggestions for improving the content. You may contact me at the address provided at the top of this Introduction.
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