Anorthosites, which contains high amounts of plagioclase felspar, can use their magnetic properties to look at mineral deopsits and magnetic anomalies on other planets. Scientists looked at anorthosite in Norway and found that they had a natural remanent magnetism and contain strong signatures of the Earth’s magnetic field direction when the rock was crystallized. Microscopic studies revealed that the anorthosites contained illmenite and hematite, both of which are weakly magnetic. Other studies showed that the submicroscopic plates of hematite and illmenite interact to show magnetic anomalies.
http://www.sciencedaily.com/releases/2008/02/080217093611.htm
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