The Iron Age
One characteristic that separates humans from animals is that we make lots of tools. Our early ancestors fashioned their first tools from bone, wood, and stone. The Stone Age takes its name from when stone implements represented the highest technology available. Later, copper and its alloy with tin (bronze) were discovered, yielding more durable weapons and tools that offered significant advantages to their possessors. The Bronze Age started during the third millennium B.C. for much of Eurasia, though its beginning and end varied widely around the world. Then around 1400 B.C. the Hittites of Asia Minor discovered that iron could be smelted from common ores to produce even more superior tools and armory, thus giving birth to the Iron Age.
But how was iron discovered? Copper's melting point (1,980° Fahrenheit) is low enough that simple fires can both reveal and smelt the ore, while iron's melting point (2,795°F) requires intentional discovery and special methods for processing. What gave the clue that iron should be sought and developed?
This gold-inlaid knife from the reign of Emperor Jahangir, the fourth Mughal ruler of India, was forged from an iron meteorite that fell on April 10, 1621. Jahangir ordered that two swords, a dagger, and a knife be made from the meteorite, which was believed to possess magical powers. Only the knife is still known to exist. An iron dagger of meteoritic origin was also discovered in the tomb of the 14th-century B.C. Egyptian pharaoh Tutankhamen in 1922.
Courtesy Freer Gallery of Art/Smithsonian Institution, Washington, D.C.
Many late Bronze Age archaeological sites actually contain artifacts made of approximately 90 percent iron. A famous example is the dagger recovered from the tomb of the 14th-century B.C. Egyptian pharaoh Tutankhamen. Chemical analyses show the dagger's "impurities" to be largely nickel, a sure sign that the iron came from a meteorite. So early metalsmiths found and used naturally smelted iron. They would have quickly realized its superiority. The Hittites and Sumerians acknowledged this connection by calling iron "fire from heaven." The Egyptian word for it means "thunderbolt of heaven," and the Assyrian term was "metal of heaven." With meteorites as an inspiration and a direct guide, the recognition of Earthly iron ores was probably inevitable. Meteorites jump-started the Iron Age.
When European explorers encountered a tribe of Inuits in northwestern Greenland in 1818, they were astounded to find knife blades, harpoon points, and engraving tools made of meteoric iron. Tools from the fabled Greenland meteorite had been found as far as 1,400 miles away, having been transported as treasured trade goods. The area has no natural metal deposits, yet the abundant availability of meteoric iron allowed the polar hunters to skip to the Iron Age and helped them survive in an extremely harsh land.
The 'Ahnighito' or Tent meteorite from Greenland on display at the American Museum of Natural History in New York City. The largest of the three Cape York meteorites recovered by Robert Peary in the late 1890s, this 34-ton hunk of iron and nickel measures 11 feet long, 7 feet high, and 5-1/2 feet thick.
Courtesy Edwin L. Aguirre with permission of the American Museum of Natural History.
Five expeditions from 1818 to 1883 failed to find the "Iron Mountain" until Robert E. Peary was led by a local guide to the site on Saviksoah Island off northern Greenland's Cape York in 1894. The meteorite was found in three primary masses, named the Tent or "Ahnighito" (34 tons), the Woman (2½ tons), and the Dog (½ ton). Over the next three years Peary's expeditions managed to load them onto ships despite savage weather, engineering problems, and having to build Greenland's only railway for transporting the behemoths. Upon arrival in New York City, the source of Greenland's Iron Age were sold to the American Museum of Natural History for $40,000, where they are now on display at the Hayden Planetarium.
Ironically, even today, 27 percent of the world's nickel comes from mines in the large Sudbury meteor crater in Ontario, Canada.