(さてつ)

さてつ
noun
iron sand; magnetite sand
nature
1. iron sand; magnetite sand
Tiny grains of iron-bearing mineral (mostly magnetite) found mixed with ordinary sand on beaches and riverbeds. Magnetic, and historically used in Japan as a raw material for tatara iron-making.
Collect iron sand with a magnet.
Iron sand is mixed in with the sand on the beach.
In old Japan, swords were made from iron sand as a raw material.

Composed of () (sand) + (てつ) (iron). Refers to the dark, magnetic granules found in sand. Famous in Japan for its use in the traditional たたら製鉄(せいてつ) (tatara iron-making) that produced steel for Japanese swords.

Common collocations

Cultural note

Iron-sand collection is a common Japanese elementary-school science experiment: children draw a magnet through beach or playground sand to see the dark iron grains gather around it.