Kamacite spindles with schreibersite

Meteorite - Balambala, IIF Iron

Kamacite spindles in iron meteorites like Balambala form through a process called "eutectic crystallization." This process is crucial in metallurgy for creating alloys. In meteoritics, specifically iron meteorites, knowing the eutectic "point" for kamacite and taenite during primary cooling helps to define a meteorite's cooling profile.

Depending upon nickel content and the rate of cooling, the interaction between kamacite and taenite can result in the formation of elongated, spindle-like structures that form discontinuous, bayonet-like spindles in a taenite matrix and are scattered in an octahedral arrangement. The larger ones are cored with schreibersite crystals.

Similar kamacite spindles occur in the Ballinoo, IIC iron (page 44). A major difference between the Ballinoo spindles and Balamba is that Ballinoo is partially recrystallized from an artificial terrestrial heating event, which is evident in the kamacite spindles.