Smith, D. G. W., Omoumi, H., & Leibovitz, D. P. (1989) The MinIdent database: some recent development. 28th International Geological Congress. Extended Abstract, 3: 138-139. [doi: 10.13140/RG.2.1.5092.7842] (pdf)

Abstract: The MinIdent database and the software for mineral identification (Smith &: Leibovitz 1984, 1986; Smith, 1986) have been successfully ported to a PC from the Amdahl mainframe on which they were developed. The “compiled” data base (used in mineral identification) plus necessary management programs can be accommodated on a 30 Mbyte hard disc. Developments presently being undertaken, will further reduce these storage requirements.

Since the publication by Smith &: Leibovitz (1986). many new data have been added and information now exists for some 4.200 mineral varieties. species. series. groups etc. Literature and data-entry errors are being identified using tests for self-consistency. and progressively eliminated.

In particular. that part of the database dealing with un-named minerals has been greatly expanded, and reorganised by year of first description. Data for un-named minerals are presently scattered throughout 100 years of earth science literature and range from vague descriptions of hand-specimen properties to complete modern analyses. The lists compiled by Hey (1962. 1963) were made the starting point. and then a wide range of journal and other literature sources used to obtain additional information and to bring the list up to date. Only those minerals for which numerical data are available have been included. Presently. nearly 600 un-named minerals appearing in the literature have been included. Once complete, this subset of the database will provide a unique resource and will allow users attempting to identify unknowns to compare their data with those for all previously described minerals and not only with those species that have received names. The use of the mineral identification software permits a numerical estimate to be obtained of the similarity between an unknown and previously described species. The immediate availability of a compilation of literature data for the latter provides a convenient indication of what other parameters might be obtained for a more unambiguous identification. The possibility also exists of adding a further category of data – for phases which have been obtained as the products of experimental work but which have not so far been found occurring naturally.

Another addition to MinIdent is a substantial list of discredited mineral names and synonyms. Entries are also included for minerals which although of dubious authenticity have not been unequivocally discredited and therefore remain in the database. At present there are about 1500 entries in the list, each of which includes a brief explanatory comment, the synonym (where applicable) and source reference(s). The scheme for naming rare earth-bearing minerals which was recently approved by the lMA has been fully implemented and, as far as possible, data associated with each rare earth variant of that species, appropriately assigned. However, the paucity of complete and reliable information on the concentrations of individual rare earths, continues to pose a problem. The re cent IMA decision to return to the original spelling of many non-English names has been implemented, although present software constraints preclude the inclusion of diacritical marks in such names.

Classification of minerals has been possible since the inception of ~dent. This facility has now been expanded so that the following divisions can be recognised where appropriate: variety, sub-species, species, series, sub-group, group, super-group, family, class and type. The top level “type” (e.g., silicates, oxides, sulphides, etc.) has been chosen to avoid ambiguity or overlap with other levels of classification previously used in the literature. Much progress has been achieved particularly with respect to rock-forming and more common minerals. For example, the full IMA amphibole classification scheme has been implemented (Goble &: Smith, 1988), and that for pyroxenes is presently being undertaken. However, much remains to be done and progress is hindered by the absence of a gene rally accepted and definitive classification scheme for minerals.

Other changes include the up-dating of the JCPDS PDF number and the entry or re-entry of the d-values for the five most intense lines from original literature sources. The algorithm that was specially developed for MinIdent to identify minerals on a very limited number of d-values has proved to work very well on pure phases. It is not intended for use with mixtures of phases.

Finally, a sub-set facility has been implemented which allows any group of minerals of interest to be selected from the database, and subsequently only these to be considered in the MATCH/IDENTIFY procedures. Such subsets are entirely flexible and could include categories such as “silicates”. “meteorite minerals” – or sets of minerals for instructional purposes. The use of subsets greatly reduces computational time for identification. It could prove extremely useful for the automation of mineral identification in combination with the analytical and image analysis capabilities of modern microbeam instruments.

References:

Goble, R.J. &: Smith, D.G.W. (1988): MinIdent: An application to the identification and
classification of amphiboles. Mineral. Petrol. v.38, p.213-227.

Hey. M.H. (1962): Chemical Index of Minerals. Brit. Mus. Nat. Hist. (London), 728 pp.

Hey, M.H. (1963): Appendix to Chemical Index of Minerals. Brit. Mus. Nat. Hist. (London) 135pp.

Smith, D.G.W. (1986): Automation of mineral identification from electron microprobe analyses. In: “Microbeam Analysis – 1986” (A. D. Romig &: W. F. Chambers. Eds.) San Francisco Press, San Francisco, U.S.A.

Smith, D.G.W. &: Leibovitz, D.P. (1986): MinIdent: A data base for minerals and a computer pro gram for their identification.

Smith D.G.W. &: Leibovitz, D.P. (1984): A computer based system for identification of minerals on the basis of composition and other properties. 27th Internat. Geol. Congr .• Moscow (1984) Abstracts v.5. p.169.

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Smith, D. G. W., & Leibovitz, D. P. (1984) A computer-based system for identification of minerals on the basis of composition and other properties. 27th International Geological Congress. Extended Abstract, 5:169. [doi: 10.13140/RG.2.1.2471.3442]

Abstract: Developments in the techniques, theory and practice of microbeam analysis over the last quarter century have resulted in a situation in which reliable compositional data can now be obtained extremely rapidly and conveniently. However, the interpretation of these data is not always so straightforward or rapid, particularly when the microanalyst is not a fully trained mineralogist or when data are obtained from one of the less common minerals or from one of a group of compositionally similar minerals. Furthermore, certain modern procedures for the automated modal analysis of rocks and other mineral aggregates require that a very large number of identifications be performed – preferably without human intervention. The system described in this paper has been developed in response to such situations.

The system uses a purpose-developed FORTRAN IV computer program “MINIDENT” different parts of which permit the creation of analytical data files, the processing of these files to produce an “index”, and the searching of the index to find the best matches with an unknown. Although the system is b~8Bed primarily on compositional data, several other properties, such 8S reflectance, refractive indices, VHN, density, etc., have been included and can be used with (or without) compositional data to seek a match with an unknown. Each mineral entry is cross referenced to the appropriate JCPDS file number. MINIDENT produces a list of the most likely matches and prints these together with an estimated ‘reliability factor’ for each match. The program can also be used to produce an alphabetical list of all minerals with certain properties – e.g., those. containing a particular element or element combination, those which have refractive indices within a certain range, etc. It can also be used to print a summary of the information included in the data-base for a given mineral. New data can be added by means of MINIDENT and is instantly included in the data base for use in subsequent searches. Considerable emphasis has been placed on making the interactive computer software easily used and understood.

Although MINIDENT is capable of providing an identification and/or list of the most likely possibilities very rapidly and on the basis of minimal input information, it is not intended that it should supercede the JCPDS powder diffraction index. That index will normally provide the more definitive answer, although the time and effort expended in making the identification will usually be much greater. A combination of the two systems also seems possible. The normal input of d-spacings and intensities to a program searching the JCPDS files could be augmented by the output from MINIDENT, thereby greatly reducing the search time involved.

At the time of preparation of this abstract, (September 1983) the basic data for more than 2000 minerals, minerals groups or mineral series are on file and these are being added to as time and funds permit. In future, it may prove possible to add other fields to this data base – not only with 8 view to making more positive identifications but also to allowing the retrieval of a more complete summary of available information on the mineral once an identification has been made.

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