The blocklike shapes in the rock were once large andalusite crystals. Now they are occupied by hundreds of white blades of kyanite that formed when the rock was deeply buried and subjected to higher pressures. Kyanite is stable at high pressures and moderate to high temperatures.
Zap! Lightning created this lodestone--a natural, permanent magnet. Steel paper clips cling better to areas where the strongest current traveled. To make a lodestone, you need: an iron ore--in this case, magnetite; tiny, oriented inclusions of another iron mineral--in this case, maghemite; a bolt of lightning.