Type specimen
A type specimen is the officially archived portion of a meteorite, kept in a research collection as the reference sample for its classification.
When a new meteorite is submitted for an official name, the Nomenclature Committee requires part of it to be deposited in an approved institution, such as a university or national museum collection with long-term curation. That reference piece is the type specimen. The usual requirement is at least 20 grams or 20 per cent of the total known mass, whichever is smaller, together with any polished thin sections used for the classification.
The idea comes from biology, where a type specimen anchors the definition of a species. For meteorites, it guarantees that future researchers can check the original classification, apply new techniques or settle disputes. This matters most for meteorites that pass into private hands, where the rest of the material may be cut up and dispersed among collectors. Without an accessible reference, a classification could not be tested.
The Meteoritical Bulletin records which institution holds the type specimen of each meteorite. Even for a celebrated meteorite such as the martian breccia NWA 7034, much of which passed through private hands, the official entry names a research institution as the type specimen holder. You cannot tell a type specimen by looking; it is defined by its documentation and catalogue records.
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