Wiktionary
hematine
n. An artificial magnetic material, a barium-strontium ferrite, used in jewellery.
Wikipedia
Hematine
Hematine (also magnetic hematite, hemalyke or hemalike) is an artificial magnetic material. Hematine is widely used in jewelry.
Although it is claimed by many that it is made from ground hematite or iron oxide mixed with a resin, analysis has demonstrated it to be an entirely artificial compound, a barium-strontium ferrite.