Maghemite is a form of iron oxide, also known as gamma
Fe2O3, with the crystalline structure (and strongly
magnetic nature) of magnetite but the composition of hematite, which can
act as a powerful catalyst. On Earth, it
is usually found only around the edges of regions of hydrothermal or magnetic
activity, where the temperature ranges from 300 to 400°C. The abundance
of water on Earth has converted much of the maghemite into a noncatalytic
form, but on Mars it has survived virtually unaltered.
It was cited by Vance Oyama in his explanation
of the results of the Viking labeled release
(LR) experiment (see Oyama's hypothesis,
about the active nature of the martian soil). Synthetic maghemite is
being studied as part of an electrically conductive and magnetizable film
in nanocomposite structures.
AND PLANETARY SCIENCE