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Geo-pic of the week: Lodestone

lodestone

Above is a picture of lodestone, which was collected from Magnet cove, Arkansas.  Lodestone is composed of iron and oxygen and is just like the mineral magnetite except, lodestone is naturally magnetic. 

Magnetic minerals are rare on earth but, they have been a crucial part of human evolution.  Discovery of magnetic lodestone by ancient people led to the invention of the compass.  The compass, in turn, revolutionized navigation, and lead to the spread of technologically advanced cultures around the world.

Scientists are still uncertain how lodestone became magnetized but, the most accepted theory holds that it forms when magnetite is struck by lightning, which has a strong magnetic field.  The fact that lodestone is primarily found at the earth’s surface supports this theory and scientists have been able to produce rock identical to lodestone by exposing magnetite to lightning. 

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