In the current paper, researchers focused on epitaxially grown magnetite single crystals. They are key indicators of the geochemical and thermal history of the carbonate-rich fracture zones of the Martian rock, they say. Magnetite crystals, apparently formed by several different high-temperature growth mechanisms, are found in several distinct mineral settings in this meteorite. With regard to whiskers, the researchers cite various evidence of epitaxial crystal growth and high-temperature origin of magnetites in the meteorite. TEM techniques allowed researchers to view the well-defined spatial orientation relationship between magnetite and carbonate crystals.
Epitaxy can occur if two similarly patterned lattice planes of crystal structures are parallel.
Furthermore, many of the epitaxially formed magnetite whiskers in the meteorite appear to be free of internal defects, the researchers say. Such is typically the case of crystals formed at elevated temperatures, while those grown at lower temperatures tend to have high densities of internal defects. Also, researchers found epitaxially formed magnetite crystals in mineral specimens from volcanoes in Indonesia and Alaska. These crystals formed at temperatures in excess of 600 degrees Celsius, researchers say. They compared these to the magnetites in the meteorite because volcanoes also exist on Mars.