Natural copper, when freshly exposed, is typically a reddish, orangish, or brownish color. However, it's more commonly seen with a green coating.
The Fresh Color of Copper
When copper is newly exposed to air (for example, when freshly mined or polished), it exhibits a distinctive metallic color. This color is best described as:
- Reddish-orange: The dominant hue is often a blend of red and orange.
- Brownish-red: Depending on the purity and surface condition, it can also appear more brownish.
The Patina Effect: Why Copper Turns Green
Over time, copper reacts with the environment, most notably with oxygen, water, and carbon dioxide. This reaction results in the formation of a green layer called patina or verdigris. This is chemically known as copper(II) carbonate. This is why you often see copper roofs, statues, and pipes exhibiting a green color.
Summary
So, while the inherent color of copper is a reddish-orange or brownish-red, the characteristic green tarnish (patina) that develops over time is much more commonly observed.
