Gibeon Meteorite Slices: The Widmanstatten Pattern
Most meteorites with a high iron contentâ€”such as the Gibeon Meteoriteâ€”were formed in the cores of asteroids at temperatures up to and over 2,500 degrees F., and were originally completely molten.
Very graduallyâ€”at a rate of perhaps 18-180 degrees F. per million yearsâ€”the liquid metal cooled and began to crystallize. In cases where the percentage of nickel to iron in the cooling mixture was "just right," two alloys, Taenite and Kamacite, would form slightly different crystal structures which grew into and over each other.
The resulting intricate designs created by this intergrowth are called "WidmanstÃ¤tten Figures" and are characteristic of many iron meteorites. Radiometric dating indicates the crystallization of Taenite and Kamacite in the Gibeon Meteorite took place more than four billion years ago!
The pieces we offer have been sliced and etched with acid to show the WidmanstÃ¤tten Figures clearly. (The etching process, by the way, is described in detail in Rocks from Space.) Despite the time and care involved in etching them, Gibeon Meteorite slices are surprisingly inexpensive!