This striking bead is made of copper firebrick from Northern Michigan. Between 1845-1890, Copper County Michigan was a copper mining hub, producing 95% of the nation's copper. As the copper was smelted, the firebricks absorbed some of the copper; this bead comes from those firebricks. A piece of American history! Copper conducts energy; healing mind, body and spirit. The perfectly round bead measures approximately 14mm outside diameter with a solid sterling core that has an inside diameter of 4.37mm. Fits all major bracelet brands. Handmade in New Hampshire.