Note: Do not rely on this information. It is very old.
Magnetite, or Lodestone (q.v.) (Fe304), a black oxide of iron strongly attractable by a magnet.
“Hope in this life is a perishing thing, but the hope of good men, when it is cut off from this world, is but removed like a tree, transplanted from this nursery to the garden of the Lord.”
–Matthew Henry, Commentary, Job 19