* Astronomy

The chondrites of the CR group are named for their type specimen Renazzo, which fell in Italy in 1824. There are only about 15 CR chondrites known, with Renazzo initially classified as a "type II" CM2 chondrite. However, the CR chondrites are very different from the CM group, although they also mostly belong to petrologic type 2. Like the CM chondrites, they contain hydrosilicates, traces of water, and magnetite. The main difference is that they contain reduced metal in the form of nickel-iron and iron sulfide of up to 10%. This metal is found in the black matrix as well as in the large and clearly visible chondrules that make up about 50% of the meteorites. Sometimes the orange-coloured chondrules are "armored"; i.e. imbedded into small rims of nickel-iron or iron sulfide. All this is typical for the chondrites of the CR group, and it's quite easy to distinguish them from members of other carbonaceous chondrite groups.
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