Magnetization of ancient ceramics

The saturation magnetization sigma of soft baked pottery appears to be dete rmined during the firing process by transitions between the iron oxides mag netite, maghemite, hematite and perhaps goethite. The finding of large vari ations in a motivated the design and construction of a 'magnetization-gravi tation', or 'MG', balance for rapid non-destructive magnetization measureme nts. The first results with this MG balance are presented: iso-sigma contou rs, typical histograms and correlations with colour features. Practical MG applications are summarized.