They made two - layer nanoparticles, each containing a core of one magnetic mineral inside a shell of another. (sciencemag.org)
There were two primary characteristics the researchers used to hone in on the origins of Devils Tower: the shape of its distinctive columns and the alignment of magnetic minerals within them. (scientificamerican.com)
To more sharply define the time period of the tools, Lepre and co-author and Lamont - Doherty colleague Dennis Kent examined magnetic minerals beneath, around and above the spots where the tools were found. (sciencedaily.com)