New property found in ancient mineral lodestone

Using the latest nanofabrication methods, a team of Rice University physicists has discovered a surprising new electronic property in one of the earliest-known and most-studied magnetic minerals on Earth -- lodestone. Also known as magnetite, lodestone was used to make compass needles as early as 900 years ago. In new research in Nature Materials, the researchers describe how super-cooled magnetite reverted from an insulator to a conductor when the voltage was altered in their experiment.