Ivuna is a carbonaceous chondrite (CI1)that fell in Mbeya, Tanzania the evening of December 16, 1938. While multiple stones may have fallen, only one 705 g piece was ever recovered.
Ivuna is the type specimen for the CI chondrite group of meteorites, which are extremely rare; only 9 are known to exist on Earth. CI meteorites are the most chemically primitive meteorites known, and are believed to have formed in the outer reaches of the solar nebula, where they were never heated to more than 50 degrees Celsius (122 degrees Fahrenheit). They are distinguished by the complete absence of chondrules and refractory inclusions, and high degree of hydration.
Current studies link the CI meteorites to C-type asteroid (162173) Ryugu, and samples returned by the JAXA Hyabusa2 spacecraft point to origins at the edge of the Solar System.
Ivuna is housed in one of the Buseck Center for Meteorite Studies nitrogen-vented cabinets; pictured here in a glass archival jar. Photo ASU/BCMS.