an iron (appliance for removing wrinkles from clothing) / (Buddhism) a vajra / cobalt

cobalt

magnetism

Solid, hard, firm.

Keeping a material's shape that does not crack or break apart; hard / Keeping one's appearance or facial expression; serious

metal

to hold, to carry something / to have, to possess / to hold up, to maintain

holding, possession / wear, durability

continuative of 持つ

ferromagnetism