I'm reminded of thermoluminescence for dating objects. Radiation creates defects in the material over time. When heated the defects release light.

Imprecise but will fink on ceramics that were fired 30 years ago vs 3000 years ago. Difficulty you need to heat a fair sized sample.

"Reads article"

Impression, author didn't understand any of what he was told.

But yes similar, over time the object picks up a faint magnetic field superimposed on the one locked in when the ceramic was made.