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Recommended classes in the Meteoritical Bulletin Database are assigned by the database editor. In most cases, this is based on the most recent classification that appears in either the Catalogue of Meteorites, MetBase, the US Antarctic Meteorite Newsletter, the Japanese Meteorite Newsletter, or the Meteoritical Bulletin. However, in a few cases it reflects differences of opinion about the proper way to classify the meteorite. The nomenclature used may also be modified by the editor to conform to an internally consistent classification scheme
The recommended classification Martian (polymict breccia) means:
"A martian meteorite that is a breccia composed of clasts of various lithologies; this martian meteorite is not assigned to the shergottite, nakhlite, or chassignite types."
The highlighted words are defined as follows:
martian meteorite: Martian meteorites are martian rocks that were ejected from Mars by impacts and later fell to the Earth as meteorites. Three well-known types are shergottites (basaltic to lherzolitic igneous rocks, named after the Shergotty, India, fall of 1865), nakhlites (clinopyroxenites or wehrlites, formed as cumulate rocks, and named after the Nakhla, Egypt, fall of 1911), and chassignites (dunitic cumulate rocks named after the Chassigny, France, fall of 1815).