Type specimen (mineralogy)

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In mineralogy, the type specimen, also known as type material, is a reference sample by which a mineral is defined. [1] Similar to the biology type methods, a mineral type specimen is a sample (or in some cases a group of samples) of a mineral to which the scientific name of that mineral is formally attached. In other words, a type specimen is an example that serves to anchor or centralize the defining features of that particular mineral.

Contents

A mineral is a scientifically named set that includes some materials and excludes others, based on a detailed published description and on the provision of type specimens, which are usually available to scientists for examination in a major museum research collection, or similar institution.

History

Whereas the system of type specimens has long-existed in the biological sciences, this is not the case in mineralogy. The recentness of the practice means that sometimes no type material exists, even for minerals discovered as recently as the twentieth century. [1] The publication of "Type specimens in mineralogy" by P.G. Embrey and M.H. Hey in 1970 stimulated much discussion on type specimens, leading to formal definitions approved by the IMA in 1987. [2]

Nowadays, deposition of the type material in a professionally curated museum is required by the Commission on New Minerals, Nomenclature and Classification of the IMA when approving a new mineral species. [3]

Types

The following definitions for kinds of type specimens were approved in 1987 by the Commission on New Minerals and Mineral Names and the Commission on Museums of the International Mineralogical Association (IMA). [1] These definitions are primarily separated by the number of specimens necessary for definition of a mineral type.

Holotype

A holotype is a single specimen from which the original description of the mineral can be determined in whole. [1] In plain English, a single object that can be used to completed define a mineral type.

Cotype

Cotypes are multiple specimens from which quantitative, but not necessary, data are obtained for the original mineral description. [2] In plain English, multiple objects are necessary to define the mineral type.

Neotype

A neotype is a new specimen for the redefinition or reexamination of a mineral when the holotype or cotypes cannot be located or, upon examination, are inadequate for study. [1] These type specimens are valuable when a mineral species is reevaluated because the original description of a mineral may be incomplete or contain errors. [3] [4] In plain English, a mineral that already possessed what was believed to be a sufficient definition, that is then subject to reexamination because of the discover of a new specimen. In some cases, this may be because the original specimens were lost.

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Holotype The example of an organism used to describe its species

A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype. Under the International Code of Zoological Nomenclature (ICZN), a holotype is one of several kinds of name-bearing types. In the International Code of Nomenclature for algae, fungi, and plants (ICN) and ICZN, the definitions of types are similar in intent but not identical in terminology or underlying concept.

Type (biology) Specimen(s) to which a scientific name is formally attached

In biology, a type is a particular specimen of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralize the defining features of that particular taxon. In older usage, a type was a taxon rather than a specimen.

In biological nomenclature, a syntype is any one of two or more biological types that is listed in a description of a taxon where no holotype was designated. Precise definitions of this and related terms for types have been established as part of the International Code of Zoological Nomenclature and the International Code of Nomenclature for algae, fungi, and plants.

Abernathyite

Abernathyite is a mineral with formula K(UO2)(AsO4)·3H2O. The mineral is named after Jesse Evrett Abernathy (1913–1963) who first noted it in 1953 in the U.S. State of Utah. It was described as a new mineral species in 1956. Abernathyite is yellow and occurs as small crystals.

<i>Agardite</i> mineral series

Agardite is a mineral group consisting of agardite-(Y), agardite-(Ce), agardite-(Nd), and agardite-(La). They comprise a group of minerals that are hydrous hydrated arsenates of rare-earth elements (REE) and copper, with the general chemical formula (REE,Ca)Cu6(AsO4)3(OH)6·3H2O. Yttrium, cerium, neodymium, lanthanum, as well as trace to minor amounts of other REEs, are present in their structure. Agardite-(Y) is probably the most often found representative. They form needle-like yellow-green (variably hued) crystals in the hexagonal crystal system. Agardite minerals are a member of the mixite structure group, which has the general chemical formula Cu2+6A(TO4)3(OH)6·3H2O, where A is a REE, Al, Ca, Pb, or Bi, and T is P or As. In addition to the four agardite minerals, the other members of the mixite mineral group are calciopetersite, goudeyite, mixite, petersite-(Ce), petersite-(Y), plumboagardite, and zálesíite.

Founded in 1958, the International Mineralogical Association (IMA) is an international group of 40 national societies. The goal is to promote the science of mineralogy and to standardize the nomenclature of the 5000 plus known mineral species. The IMA is affiliated with the International Union of Geological Sciences (IUGS).

Paratype

In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype. Often there is more than one paratype. Paratypes are usually held in museum research collections.

Nickel–Strunz classification is a scheme for categorizing minerals based upon their chemical composition, introduced by German mineralogist Karl Hugo Strunz in his Mineralogische Tabellen (1941). The 4th and the 5th edition was also edited by Christel Tennyson (1966). It was followed by A.S. Povarennykh with a modified classification.

Pimelite

Pimelite was discredited as a mineral species by the International Mineralogical Association (IMA) in 2006, in an article which suggests that “pimelite” specimens are probably willemseite, or kerolite. This was a mass discreditation, and not based on any re-examination of the type material. Nevertheless, a considerable number of papers have been written, verifying that pimelite is a nickel-dominant smectite. It is always possible to redefine a mineral wrongly discredited.

Georgerobinsonite, named for George Willard Robinson, is a lead chromate mineral with formula Pb4(CrO4)2(OH)2FCl. It exhibits very small, transparent crystals with a bright orange-red color. It was obtained from the Mammoth-St. Anthony Mine in Arizona in the 1940s and identified in 2009.

Magnesiopascoite is a bright orange mineral with formula Ca2Mg(V10O28)·16H2O. It was discovered in the U.S. state of Utah and formally described in 2008. The mineral's name dervies from its status as the magnesium analogue of pascoite.

Ruizite

Ruizite is a sorosilicate mineral with formula Ca2Mn2Si4O11(OH)4·2H2O. It was discovered at the Christmas mine in Christmas, Arizona, and described in 1977. The mineral is named for discoverer Joe Ana Ruiz.

Junitoite

Junitoite is a mineral with formula CaZn2Si2O7·H2O. It was discovered at the Christmas mine in Christmas, Arizona, and described in 1976. The mineral is named for mineral chemist Jun Ito (1926–1978).

Georgius Agricola is considered the 'father of mineralogy'. Nicolas Steno founded the stratigraphy, the geology characterizes the rocks in each layer and the mineralogy characterizes the minerals in each rock. The chemical elements were discovered in identified minerals and with the help of the identified elements the mineral crystal structure could be described. One milestone was the discovery of the geometrical law of crystallization by René Just Haüy, a further development of the work by Nicolas Steno and Jean-Baptiste L. Romé de l'Isle. Important contributions came from some Saxon "Bergraths"/ Freiberg Mining Academy: Johann F. Henckel, Abraham Gottlob Werner and his students. Other milestones were the notion that metals are elements too and the periodic table of the elements by Dmitri Ivanovich Mendeleev. The overview of the organic bonds by Kekulé was necessary to understand the silicates, first refinements described by Bragg and Machatschki; and it was only possibly to understand a crystal structure with Dalton's atomic theory, the notion of atomic orbital and Goldschmidt's explanations. Specific gravity, streak and X-ray powder diffraction are quite specific for a Nickel-Strunz identifier. Nowadays, non-destructive electron microprobe analysis is used to get the empirical formula of a mineral. Finally, the International Zeolite Association (IZA) took care of the zeolite frameworks.

Joseph (Joe) Anthony Mandarino OC, FRSC was an American-Canadian mineralogist and crystallographer.

Widgiemoolthalite

Widgiemoolthalite is a rare hydrated nickel(II) carbonate mineral with the chemical formula (Ni,Mg)5(CO3)4(OH)2·5H2O. Usually bluish-green in color, it is a brittle mineral formed during the weathering of nickel sulfide. Present on gaspéite surfaces, widgiemoolthalite has a Mohs scale hardness of 3.5 and an unknown though likely disordered crystal structure. Widgiemoolthalite was first discovered in 1992 in Widgiemooltha, Western Australia, which is to date its only known source. It was named the following year by the three researchers who first reported its existence, Ernest H. Nickel, Bruce W. Robinson, and William G. Mumme.

Roymillerite is a solid colorless transparent crystalline mineral. It has a non-trivial crystal structure.

References

  1. 1 2 3 4 5 Dunn, p. 1269.
  2. 1 2 Dunn, pp. 1269–70.
  3. 1 2 "The Online Type Specimen Catalogue Germany" (PDF). Elements. Deutsche Mineralogische Gesellschaft. June 2007. Retrieved July 25, 2012.
  4. ↑ Nickel, p. 8.
Bibliography
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