50 Fun Facts About Copper

What is the chemical symbol for copper?

It comes from the Latin cuprum; Co is cobalt and Cr is chromium.

What is copper's atomic number?

Its neighbours in group 11, silver and gold, are 47 and 79.

From which Latin word does the symbol Cu derive?

The word evolved from aes cyprium, 'metal of Cyprus'.

Which island gave copper its name?

Romans called it aes cyprium, and the island was sacred to Aphrodite, copper's goddess.

Which pure metal is the only one with higher electrical conductivity than copper?

Copper's softness partly explains its conductivity, which is why it dominates wiring.

What colour is a freshly exposed surface of pure copper?

It is one of very few metals whose natural colour is not grey or silver.

What is the green patina on old copper roofs and statues called?

It is a layer of copper carbonate that protects the metal beneath.

Alloying copper with which metal produced bronze, in around 3500 BC?

It was the first time humans deliberately alloyed one metal with another.

What is an alloy of copper and zinc called?

Typically it is about two-thirds copper and one-third zinc.

What percentage of a US five-cent 'nickel' is actually copper?

The coin is a homogeneous cupronickel alloy, only a quarter nickel.

Which country is the world's largest copper producer?

It supplied around 70% of US refined copper imports through 2024.

Which mine near Calama is the world's largest open-pit copper mine by excavated volume?

Nicknamed Chuqui, it sits 2,850 m above sea level and is 850 m deep.

In which US state is Bingham Canyon, the deepest open-pit mine on Earth?

Southwest of Salt Lake City, it has produced more copper than any mine in history.

Which mining group owns the Bingham Canyon copper mine?

It has been in production since 1906 and its pit is more than 1,200 metres deep.

Which brassy-yellow sulfide is the most abundant copper ore mineral?

Its formula is CuFeS2 and its streak is a diagnostic green-tinged black.

How pure was the copper of the axe blade found with Ötzi the Iceman?

High arsenic levels in his hair suggest he was involved in smelting.

How thick is the copper skin of the Statue of Liberty?

The sheets were shaped by repoussé, heated and struck with wooden hammers.

By which year had a green patina entirely covered the Statue of Liberty?

Congress voted money to paint it before engineers found the patina was protective.

What did the Army Corps of Engineers conclude about the Statue of Liberty's patina?

They said it 'softened the outlines of the Statue and made it beautiful', so only the inside was painted.

Where was the largest lump of native copper ever found, 420 tonnes, discovered in 1857?

The Keweenaw district led American copper output until Butte eclipsed it in the 1880s.

Roughly what share of all copper ever mined is estimated to still be in use?

Like aluminium, it can be recycled endlessly with no loss of quality.

Copper ranks where among the most abundant elements in Earth's crust?

At about 50 parts per million it trails zinc's 75 ppm.

Which heavenly body and goddess represented copper in mythology and alchemy?

It was the brightest body after the Sun and Moon, matching the most lustrous metal after gold and silver.

Which synthetic copper pigment was first used in ancient Egypt around 3250 BC?

Its recipe was lost after the fourth century AD and only reconstructed in modern times.

Which copper-based protein gives horseshoe crabs and most molluscs blue blood?

Iron-based hemoglobin makes our blood red instead.

Which genetic disorder causes copper to accumulate in body tissues?

It can lead to cirrhosis of the liver and psychiatric symptoms.

What is the single biggest use of copper, taking about 60% of it?

Roofing and plumbing take about 20% and machinery 15%.

Which airliner uses aluminium wire instead of copper for electrical power transmission?

Properly sized aluminium wire avoids the fire hazards seen in 1970s US homes.

When did aluminium wiring briefly replace copper in many US homes, causing fires?

Improper design was the problem; larger-gauge aluminium wire is still installed today.

The Great Copper Mountain, which funded Sweden's 17th-century wars, was in which town?

It supplied two-thirds of Europe's copper and operated until 1992.

In which city did the first modern copper electroplating plant open in 1876?

The Norddeutsche Affinerie is still one of Europe's biggest copper refiners.

Flash smelting, used for half the world's primary copper, was developed in which country?

Outokumpu first applied it at Harjavalta in 1949.

In which year was CIPEC, the copper exporters' cartel modelled on OPEC, dissolved?

Formed in 1967, it never had OPEC's clout because the United States never joined.

Which country became the world's largest importer of copper in 2008?

It now accounts for over half of global copper demand.

In which year did the US cent switch from 95% copper to copper-plated zinc?

The copper in the coin had begun to be worth more than one cent.

What were US cents briefly made of in 1943 because copper was needed for the war?

A few copper 1943 cents struck on leftover planchets are now prized rarities.

The vineyard fungicide Bordeaux mixture is based on which copper(II) compound?

Its blue pentahydrate is the most familiar copper compound in the laboratory.

Which navy pioneered copper sheathing of ships' hulls in the 18th century?

Copper is biostatic, so barnacles and mussels will not grow on it.

Which city's subway fitted antimicrobial copper-zinc handrails at some 30 stations?

Copper alloys kill more than 99.9% of disease-causing bacteria within two hours.

Which US state ranked first in copper production early in the twentieth century?

Morenci in Arizona and Bingham Canyon in Utah are vast porphyry deposits.

The Mississippian copper plates were found around which ancient North American city?

Copper nuggets from the Great Lakes were hammered and annealed there around 1000–1300 AD.

In which country was the oldest known Andean copper artifact, a 1000 BC mask, found?

It suggests the southern Andes were an early centre of copper working alongside Peru.

Which metal did Sub-Saharan Africans long consider less precious than copper?

Local gold deposits were ignored until Portuguese and Arab traders arrived.

Which Japanese decorative alloy of copper with 4–10% gold can be patinated blue-black?

It was prized for sword fittings.

Copper cookware is especially useful in the kitchen for whipping what?

With acidic or alkaline foods it can leave a metallic taste.

How old is the native copper pendant from northern Iraq, the earliest known copper use?

Before copper, gold and meteoric iron were the only metals humans used.

Alderley Edge, mined for copper around 2280–1890 BC, is in which English county?

Its Bronze Age workings were carbon-dated.

Copper is the third most recycled metal by volume, after which two?

Recycled copper now supplies about one-third of global demand.

Roughly how much copper does a battery electric vehicle contain?

A petrol car of 2023 carried about 24.5 kg.

Roughly what share of naturally occurring copper is the stable isotope copper-63?

Copper has 29 isotopes in all, but only copper-63 and copper-65 are stable; both have a nuclear spin of 3/2.