The ores are, as a rule, dull and earthy, and it is only when
crystalline that they present a brilliantly metallic or attractive
appearance. We derive our iron almost wholly from stratified
sedimentary rocks, instead of from crystalline rocks, which means
that it is not in its original condition, but has been extracted from
older rocks, and sorted and redeposited by the agency of water.
6 IRON.
Our supply is consequently not limited to rocks of any particular
geological period, and we can use the ores indifferently, whether
formed millions of years ago, or within the lives of living people.
