rumurutiite NWA2069

NWA2060, a rumurutitte. © T. E. Bunch.

A rumurutiite is a rare type of chondrite named for the Rumuruti meteorite that fell in Kenya (0° 16' N, 36° 32' E) on January 28, 1934. Before the present classification of R chondrites (rumuruiites), three unusual specimens were known as Carlisle-Lakes-type chondrites for the first of them to be found in Australia in 1977. In 1993, Rumuruti, previously considered to be an anomalous chondrite, was recognized as belonging to the same group and the terms "R chondrite" and "rumurutiite" came into being .


The R chondrites differ from other chondrite groups in having a greater proportion of (iron-rich) olivine, a lower proportion of pyroxene, and virtually no iron-nickel metal – the iron being either oxidized or in the form of iron sulfides. The iron-rich olivines and iron oxides give most R chondrites a distinctive red coloration.


Rumurutiites contain fewer chondrules than do ordinary chondrites or enstatite chondrites, but they often contain xenolithic inclusions that point to a regolith origin on the surface of an asteroid. This ancestry is also indicated by the fact that most R group members contain high amounts of noble gases implanted in the rock by the solar wind.