Zirconium was identified in 1789 by Martin Heinrich Klaproth, who recognised a new earth in the gemstone zircon; the impure metal was first isolated by Berzelius in 1824. The name comes from zircon, a stone whose own name passes through Arabic and ultimately from the Persian zargun, meaning gold-coloured. Zirconium is a strong, corrosion-resistant metal notable for its low absorption of neutrons, which makes it valuable for the cladding of nuclear fuel. Highly resistant to corrosion and nearly transparent to neutrons, zirconium is prized for the tubing that jackets nuclear fuel rods, and it is used in chemical-plant equipment, in tough ceramics, and, as cubic zirconia, as a widespread diamond simulant.
Zircon crystals are exceptionally durable and chemically resistant, which makes them one of geology's most valuable clocks: tiny zircon grains from the Jack Hills of Western Australia have been dated to more than 4.4 billion years old, among the oldest known materials on Earth's surface and a key piece of evidence for conditions in the planet's earliest history. Zirconium's chemical twin, hafnium, hides in the same ores and was not recognised as a separate element until 1923, since the two behave almost identically; even today commercial zirconium typically still carries a small residual fraction of hafnium unless specifically purified for nuclear use, where hafnium's neutron-absorbing behaviour would be a serious contaminant.