Modern life as we know it simply wouldn’t be possible without copper. We rely on copper for telecommunication, for heating, and for almost everything electrical that we use in our daily lives. By some measures, we each require as much as 680 kilograms of copper to enjoy an advanced standard of living, if you consider everything from transport to telephones. There can easily be 180 kilograms of copper within a single modern home – but where on earth is all of this copper? Read on to find out.

1. It’s in your jewellery

 Even very high quality gold jewellery is rarely 100% gold. Gold is, in fact, too soft to make jewellery that can withstand daily wear, so a small amount of copper (or zinc or nickel) is usually added during the manufacturing process. While an item of jewellery that is 24 carat is typically pure gold without the addition of other metals, standards for purity do vary from market to market. In China, for instance, “pure gold” may only contain a minimum of 99% gold.

The process of mixing other metals with 24 carat gold (called alloying) makes gold less malleable, but it’s also done in order to change its colour. Increasingly popular rose gold owes its pinkish tone to the addition of copper – 8.4% copper in the case of 22 karat rose gold.

The same is true of silver jewellery, most of which is sterling silver, rather than pure (far softer) silver. Sterling silver is an alloy comprised of 92.5% silver and 7.5% other metals, most often copper. The number 925 that you often see as a hallmark engraved on jewellery to verify sterling silver represents this 92.5% minimum. This standard for sterling silver was first established by Henry II in the 12th century, when English coinage first had 7.5% copper added during minting.

Even very high quality gold jewellery is rarely 100% gold. Gold is, in fact, too soft to make jewellery that can withstand daily wear, so a small amount of copper is usually added during the manufacturing process.

2. It’s in monuments, architecture, and construction around the world

Copper has historically gone in and out of fashion as a building material. When construction of the Statue of Liberty began in 1876, copper was the material of choice – 179,000 pounds of it, to be precise.

Copper isn’t just a durable material that stands the test of time. When exposed to the elements, its natural oxidation process creates a very aesthetically pleasing result: the blue-green layer that Lady Liberty wears particularly well. This layer (or patina) varies from attractive shades of blue and green in colour to black and brown, but it also serves a practical purpose. Although very thin, the patina that forms during environmental exposure protects the underlying copper, improving its durability and reducing the need for regular maintenance. It’s no wonder that copper has been the material of choice for roofs, gutters, and chimney caps for hundreds of years, particularly in colder climates in countries like Canada.

3. It’s in alloys throughout homes and public places

You may not have realised that all the little brass details in homes, schools, and offices are partly comprised of copper. Brass is an alloy of zinc and copper, and the latter’s naturally antibacterial properties are immensely useful for making doorknobs and handrails in busy places where germs abound. Furniture and decorative flourishes like bronze chandeliers contain copper too. (Bronze is a copper-nickel alloy.)

Copper pots and pans also have a purpose other than looking attractive. Professional chefs prefer cooking with copper kitchenware because its heats up uniformly, preventing heat spots. 

4. It’s in your wallet

At some stage or another, most countries have used trusty old copper to mint their coins. Today, Britain’s two lowest value coins (1p and 2p) are made of copper-plated steel, having previously been 97% copper. When copper prices surged in the mid-2000s, the intrinsic value of these majority copper coins would’ve amounted to double their face value if they’d been melted down. Copper-coloured coins are still colloquially called “coppers” in Britain, although a “copper” can also refer to a policeman.

The American “cop” also has its roots in the metal: policemen in the United States used to wear uniforms with copper buttons. Present-day American coins are comprised of a solid copper core with an outer layer of copper-nickel alloy, and copper was chosen for Euro coins partly because it allows for easy re-moulding. Coins made from copper or zinc alloys produce a very specific electrical resistance and conductivity, which lets vending machines know whether a coin is legal tender or not.

While copper-clad steel was used to mint coins in Zambia until the late eighties, today the only trace of copper you’ll detect in the currency is the image of miners working in a copper mine, printed on the reverse of the twenty kwacha note.

5. It’s in all your electronics and appliances

Copper has been perhaps the most influential metal to humankind and our technological advancement. Copper’s history may go back as far as 10,000 years, and was probably the earliest non-precious metal used by the Sumerians and Chaldeans of Mesopotamia some 6,000 years ago. In modern technology, copper is indispensable.

Practically all your electronics contain copper, from smartphones, to computers, to televisions, to cell phones. So do your household appliances: refrigerators, washing machines, dryers, microwaves, and dishwashers all contain copper wiring. Because of copper’s high degree of thermal conductivity, hot water storage tanks are lined with copper plating, and household heating elements like stoves and electric kettles are copper. Copper is an excellent electrical conductor, is strong yet malleable, and resistant to corrosion, so it’s an obvious choice for appliance manufacturing.

But perhaps the most common household use of copper is in plumbing. Although cheaper plastic piping is on the rise, over 85% of homes in the United States utilise copper plumbing systems.

Copper for sustainable households

 Plastic may have short-term appeal when it comes to household features like piping. But copper’s wide-ranging applications and cost-effectiveness have made it a household favourite for a remarkably long time. As environmental sustainability increasingly enters public consciousness, a material like copper that is 100% recycle may be the only feasible solution for maintaining the modern – but copper-reliant – lifestyles to which we’re now accustomed.

See also: Five Things You Didn’t Know about Copper and Green Tech