The rock magnetite can only very rarely lose all of its magnetism. It is an important source and tool for magnetism and the testing of equipment in laboratories.

Earth's magnetic orientation is locked into the rock when the rock cools

No, because Earth's magnetism "flips" about every half million years. When rock form from the cooling lava of volcanoes, the particular magnetic pattern at the time is "frozen" into the rocks. This was evidence that the alternating pattern of the rock has been slowly spreading out as the new crust is formed.

The first literary reference to magnetism was the 4th century BCE in China.

improvements in technology like drilling for rock samples and instruments that measure magnetism of the iron in the sea floor rock