Steel
Galvanized steel wire is the most common paperclip material. This material doesn't rust, and the thickness of the wire promotes sturdy shapes. A paperclip machine forms the wire into the three-bend paperclip design known as the Gem shape. Some steel paperclips are coated in plastic for colorful design purposes.
Metal Alloys
Metal alloys, such as copper, brass and bronze, are softer than steel but are still capable of being ideal paperclips. Most likely, a metal alloy paperclip will be coated in plastic.
Plastic
Plastic is melted down and formed into the common oval-within-oval paperclip shape. Although colorful, plastic is not as sturdy as metal, and entirely plastic paperclips aren't as common in the workplace as metal paperclips. As noted, some metal paperclips are coated with plastic.
Fun Fact
The world's largest paperclip is said to weigh about 4,000 lb. because it is made of solid steel.
History
The three-bend paperclip design wasn't patented during its introduction into society in the 19th century. It took many years before it was patented along with the machine that creates the design.
Tip
The galvanized steel used to make paperclips does not rust like other types of steel. Using galvanized steel paperclips keeps papers clear of rust.