If you come into contact with copper and brass in your daily life, it might not be that easy to tell them apart. Which one is more valuable? How are they produced? What are they best used for? These questions might be easy for a metallurgist, but for the average person it’s not so obvious, so here’s the scoop.
Copper is an element, meaning it’s made of a single kind of atom. Of course, like all ores, we dig copper up out of the ground, and it’s often found contaminated with other metals. Copper is one of the oldest metals humans have ever been able to work with, because it’s sometimes found in a state right there in the ground that’s already ready to use. We acquire most of our copper from open mines (in the form of copper sulfides) and recycling.
Today, copper is in higher and higher demand every year and its price is several dollars per pound. It’s really good for conducting electricity and we use it in a lot of water pipes in the U.S. because it’s durable and easy to recycle. You’ll also sometimes see copper put in place in order to make surfaces “antimicrobial”, because it has natural properties that destroy several kinds of microorganisms including some bacteria, viruses, and fungi. Copper resists corrosion and is often used in buildings, but it will oxidize and turn into that familiar green color (that’s what the Statue of Liberty is covered with!).
Brass is an alloy, which means it’s NOT an element — it’s made of a combination of two or more other metals; in this case, copper and zinc. Right off the bat, that’s one obvious difference … brass is artificial and can’t be made without copper. The difference between brass and bronze, another alloy, used to be considered important, but metallurgists today may refer to both of them as just “copper alloys”.
Originally, humans didn’t even realize that zinc was a metal, and historians believe we probably started making brass just by mining and smelting copper which happened to have a lot of zinc in it naturally. Today, we alloy the metals together on purpose in a process called “speltering”, which makes it relatively easy to control the exact ratio of zinc being used, allowing us to create brass objects with precise characteristics. Brass has mostly been used for decorations; it’s shiny and looks kind of like gold, but it’s a lot cheaper. We use it for little doorknobs and hinges, especially if we want them to look pretty. It’s also quite practical though, because bronze is easy to work with and still durable and good at conducting electricity, similar to copper.
One of its other uses is in places where we need friction to be low because two metals are constantly rubbing against each other inside a machine — gears, locks, zippers, etc. Brass won’t make sparks when it’s rubbed on itself, so we use it in places where you need metal but desperately need to avoid starting a fire; pretty much anywhere near materials which explode into flames. Finally, if you ever played in the high school band, you may remember the term “brass section”; many instruments like trumpets and bells are made out of brass.