Type mineral specimens are reference samples for the definition of mineral species. The holotype mineral specimens represent the material used to obtain data for the original description of a new mineral species. The definition of a holotype (as well as cotypes and types) is necessary to clear out doubts or questions, which could arise from erroneous or incomplete original descriptions. Incompleteness occurs due to the fact that the relevance of certain attributes of the holotype were not known at the time of the original description or scientific instruments necessary for the determination of certain attributes did not exist. Therefore it is essential to keep type specimens available for scientific reexaminations.
In consequence - and for their historical value as a new discovery - such type mineral specimens are kept in permanent scientific depositories to guarantee their availability and their professional curation at any time. Currently the Working Group Mineralogical Museums and Collections of the German Mineralogical Society (DMG) is compiling this online type specimen catalogue for type materials retained in Germany.
The illustrated catalogue lists all proven type specimens, the museums housing the specimens and the scientists in charge. It also offers a free-download geo reference file, which links type localities and sites of the collections with GoogleEarth. Furthermore the type minerals are described in detail.