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Some chondrites don't fit easily into the established groups, although they can be clearly identified as - mostly unequilibrated - chondrites. They are designated as C ungrouped or C UNGR and they probably represent other parent bodies of ordinary or less ordinary chondrites or source regions of the primordial solar nebula. Some of them are unique samples, while others show certain relations to each other and/or to established groups of chondrites.
Prominent examples are the rather beautiful and chondrule-rich meteorites Hammadah al Hamra 180, and Dhofar 535. Others include our own paired finds Sahara 97009, Sahara 97039, and Sahara 97042, comprising a total known of just a bit more than 240g for this unusual chondrite. Sahara 97009, 97039, and 97042 have fayalite contents near the top of the LL range, but have O-isotopes and bulk composition that are distinct from LL chondrites, showing that they must have had their origin on a distinct parent body.
Future discoveries and finds from the hot and cold deserts might allow us to group these finds together with similar stones. Until then, they will remain ungrouped, but not less enigmatic.