Diane Haska, age 13, of Flushing, New York, for her question:
What do prospectors mean by fool's gold?
For centuries, gold has reigned as king of the precious metals. As recently as a gen¬eration ago, prospectors hunted for gold and turned up their noses at anything less. A certain golden colored shiny metal often occurs with deposits of gold. Prospectors called it fool's gold and laughed at people who mistook it for the real thing.
Nowadays, no sensible prospector walks away from a deposit of fool's gold. Chances are, he does not even call it fool's gold. He more likely whoops joyfully that he has struck a deposit of iron pyrite and prances off to take the steps necessary to stake his claim. His granddaddy would have tested a bit of the shiny yellow metal in a hot tub of soapy laundry. If it became discolored, he scoffed and said "Fool's gold" then went on his treasure hunting way.
But fashions in minerals change. And pyrite certainly has come back into style. Its ancient name myrite means "fire stone" because it is hard enough to strike sparks when whacked with a brisk blow. Before the tinderbox and then matches were invented, a hard lump of brassy, streaky pyrite was a very valuable possession. Then came the era of the gold rushers with but one mineral on their minds. Since pyrite can fool even an expert until he tests it, pyrite was called fool's gold.
Flakes of pyrite occurring in gold bearing quartz shine like flakes of gold. Rocky lumps are streaked with dark green and brassy yellow and often embedded with yellow metallic crystals. Gold, however, is not stained with streaks of tarnish. It is soft and pliable while flinty pyrite breaks under the hammer. Pyrite is more than twice as hard as gold and five times as heavy as water.
Iron pyrite is a compound of iron and sulphur, though most samples contain other minerals. Some five million tons of pyrite ores are mined every year and there must be good reason for all this toil. The industrial world has found many new chores for the old fire¬stone. Yellowish chalcopyrite tends to tarnish with rainbow colors. This ore of iron pyrite and copper is a source of copper. Other pyrite ores contain worthwhile quotas of nickel and lead, zinc or cobalt. Some samples make fo61s of the treasure hunters who named pyrite fool's gold. They actually contain traces of real gold.
Most pyrite is mined for its sulphur content which is processed to make sulphuric acid. This busy chemical does most of its work behind the scenes and the Age of Industry needs millions of tons of it every year. Sulphuric acid helps to refine petroleum and steels. It has a role in manufacturing soaps, glues and gelatins and in certain printing processes. But most sulphuric acid helps to make rayon and when this work is done it may be reprocessed into soil fertilizer.
The earth has plentiful deposits of pyrite, usually mixed with various rocks. It may occur in thin papery layers sandwiched between slabs of slate, shale and even coal. Grains and granules often occur in beds of granite and other fire formed rocks. Flakes and grains of this so called fool's gold also may occur embedded in milky white quartz, along with fragments of real gold.