Copper is an essential mineral found in plant life and in the human body & it is also a metal alloy with a reddish-orange color. The use of copper dates back over 10,000 years.
The Egyptians were the first to create metal alloys from copper – bronze (copper & tin) and brass (copper & zinc). The metal was highly prized in its natural form, as well as for use as an alloy. The more copper a person owned, the greater their social status within society. Hieroglyphics depict that not only was copper valuable, but that copper jewelers & the owners of copper held an increased status in that era. Native Americans still value copper jewelry highly. In fact, many Native American reservations still produce copper jewelry with bracelets, pendants & earrings containing Native American markings & etchings being a popular tourist souvenir.
Copper is a naturally reactive metal, meaning that it constantly changes color as the metal reacts to oxygen in our environment. The range of colors begins with unexposed copper being salmon pink to varying shades of browns, then to assorted hues of blues & greens
When jewelry is made with copper, it can react with sweat, lotion, & other products on your skin causing it to oxidize. When copper oxidizes, it goes through chemical reactions that more than likely will transfer copper carbonate onto your skin. Simply put, copper reacts to our skin's chemistry - some of us have more acidic skin than others. Some people really like the result of a patinaed(dark) copper. If you see green coloring on the skin it is harmless and comes off with soap and water.
FUN FACT
The Statue of Liberty is made entirely of copper. Originally, the statue was the color of a brand new penny, but over time, as the metal oxidized and other chemical reactions occurred, the statue developed its green patina, one of its defining features.