Type material

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In mineralogy , the type material , also known as type level , is that reference material or reference level at which or at which a mineral has been described and defined. It is therefore the material or the stages at which the properties that were determined for characterization as a new mineral were determined.

Type types

The following definitions for the different types of type materials were approved in 1987 by the then "Commission on New Minerals and Mineral Names" (today "Commission on New Minerals Nomenclature and Classification") and the "Commission on Museums" of the International Mineralogical Association (IMA) .

  • Holotype : A holotype is a single stage at which the original description of a mineral has been made.

“Holotype: A single specimen (designated by the author) from which all the data for the original description were obtained. Where portions of such a specimen have been sent to other museums for preservation, the author will designate each of these as 'part often the holotype'. "

“Holotype: A single level (determined by the author) at which all data for the original description in the type publication has been obtained. Where parts of such a step have been transferred to other museums for safekeeping, the author will mark each part of it as 'part of the holotype'. "

- Pete J. Dunn, Joseph A. Mandarino : Formal definitions of type mineral specimens
  • Cotyp : cotypes are several stages at which data have been determined for the original mineral Description quantitatively.

“Cotype: Specimens (designated by the author) as those used to obtain quantitative data for the original description. Specimens examined only visually should not be considered cotypes. "

“Cotype: Several levels (set by the author) used to obtain quantitative data for the original description [of the mineral]. Stages that were only examined visually are not considered to be cotypes. "

- Pete J. Dunn, Joseph A. Mandarino : Formal definitions of type mineral specimens
  • Neotype : A neotype is a stage that is used to redetermine or re-examine a mineral if the holotype or cotypes cannot be found or - upon examination - prove to be unsuitable for an examination.

“Neotype: A specimen chosen by the author of a redefinition or re-examination of a species to represent the species when the holotype or cotypes cannot be found. It must be shown that every attempt has been made to locate the originally described material. Neotypes can also be designated when examination of all holotypes and cotypes has shown that the definitive unit-cell parameters and chemical composition cannot be experimentally determined. All neotypes require the approval of the Commission on New Minerals and Mineral Names of the International Mineralogical Association. "

“Neotype: A level selected by the author for a redefinition or re-examination of a species if holotype or cotypes can no longer be found. It must be shown that every possible attempt has been made to identify the original material. Neotypes can also be specified if the investigation of all holotypes and cotypes has shown that the parameters for the unit cell and the chemical composition cannot be determined experimentally with the material available. All neotypes require approval from the "Commission on New Minerals Nomenclature and Classification". "

- Pete J. Dunn, Joseph A. Mandarino : Formal definitions of type mineral specimens

Intended purpose

Type mineral grades are the material that is used to determine the data for the original description of a new mineral species. They are therefore the only evidence for the test results. The definition of a type level (ideally holotype or cotype) is also necessary in order to be able to answer doubts and questions that arise from incorrect or incomplete original descriptions. Therefore, whenever possible, the redefinition, discrediting or revalidation of a mineral should be based on the examination of the type material.

history

While the system of type materials has existed for a long time in biology , this is not the case in mineralogy . The novelty of this practice means that sometimes no type material exists. This is even true of minerals that were only discovered in the 20th century. The publication "Type specimens in mineralogy" by Peter G. Embrey and Max Hutchinson Hey in 1970 spurred the discussion on type grades of minerals and led to the formal definition of type material in mineralogy, approved by the IMA in 1987.

Today, depositing the type material in a museum supervised by a professional curator is an indispensable requirement for the recognition of a new mineral by the “Commission on New Minerals Nomenclature and Classification”. Usually the location of the deposit and the collection number of the type material are given in the type publication. The "Commission on Museums" of the IMA maintains a catalog of type mineral specimens, in which the type publication for a mineral as well as the type of type material, its storage location and the collection number of the relevant museum are specified. For all type levels deposited in museums in Germany, information about them is also compiled in the “Type Mineral Catalog Germany”.

For some countries there are written compilations of the minerals discovered and described on their territories and the dumping of the corresponding type material, e.g. B. for Canada, Italy, the former Soviet Union and Switzerland.

Individual evidence

  1. ↑ a b c d e f g Pete J. Dunn, Joseph A. Mandarino: Formal definitions of type mineral specimens . In: The Canadian Mineralogist . tape 25 , no. 3 , 1987, pp. 571–572 ( rruff.info [PDF; 165 kB ; accessed on August 29, 2019]).
  2. ^ A b Ernest H. Nickel, Joel D. Grice: The IMA Commission on New Minerals and Mineral Names: Procedure and Guidelines on Mineral Nomenclature, 1998 . In: The Canadian Mineralogist . tape 36 , no. 1 , 1998, p. 1–16 ( minsocam.org [PDF; 336 kB ; accessed on January 12, 2018]).
  3. ^ A b Jochen Schlueter, Reinhardt Kurtz: The Online Type Specimen Catalog Germany . In: Elements . tape 3 , no. 3 , 2007, p. 214 ( elementsmagazine.org [PDF; 322 kB ; accessed on January 12, 2018]).
  4. ↑ Peter G. Embrey, Max Hutchinson Hey : “Type” specimens in mineralogy . In: The Mineralogical Record . tape 1 , no. 3 , 1970, p. 102-104 .
  5. ^ Catalog of type mineral specimens (CTMS). In: ima-cm.org. International Mineralogical Association - Commission on Museums, accessed August 29, 2019 .
  6. ↑ Type mineral catalog Germany. In: typmineral.uni-hamburg.de. University of Hamburg , accessed on August 29, 2019 .
  7. ^ László Horváth: Mineral Species discovered in Canada and species named after Canadians (The Canadian Mineralogist Special Publication 6) . 1st edition. Mineralogical Association of Canada, Ottawa 2003, ISBN 0-921294-40-9 .
  8. ↑ Marco E. Ciriotti, Lorenza Fascio, Marco Pasero: Italian Type Minerals . 1st edition. Edizioni Plus - Università di Pisa, Pisa 2009, ISBN 978-88-8492-592-3 .
  9. ^ Igor V. Pekov: Minerals first discovered on the territory of the former Soviet Union . 1st edition. Ocean Pictures, Moscow 1998, ISBN 5-900395-16-2 .
  10. ^ Philippe Roth: Minerals first discovered in Switzerland and minerals named after Swiss individuals . 1st edition. Kristallografik Verlag, Achberg 2007, ISBN 3-9807561-8-1 .