Native Copper
Native copper is the element copper, Cu, found as a metal in nature. It forms branching, tree-like masses and sheets of a reddish metallic color, and it weathers to green. It was probably the first metal used by humans.
Native copper is the element copper, Cu, found as a metal in nature. It forms branching, tree-like masses and sheets of a reddish metallic color, and it weathers to green. It was probably the first metal used by humans.
🪨 Geology Guide Specimen: Open Native Copper in the CRV Science Rock & Mineral ID Guide to log the specimen, compare it with the other 8 mineral classes of Dana / Strunz Classes, and test your eye in LithoClade.
Dendrites and Hackly Fracture: How Do You Recognize It?
Native copper has a hardness of 2.5 to 3 and a density of about 8.9 grams per cubic centimeter. It is malleable and breaks with a jagged, "hackly" surface, and fresh surfaces are copper-red but dull to brown and then green as a thin layer of carbonate forms.
Keweenaw Copper: Where Does It Form?
The largest deposit of native copper is the Keweenaw Peninsula of Michigan, where it fills spaces in ancient basalt lava flows and in conglomerate. Native Americans collected and worked that copper for thousands of years.
First Metal: Why Was It Important?
Native Copper at a Glance
| Property | Value |
|---|---|
| Type / variety | Cu • Isometric Dendritic Native Metal |
| Composition | Cu (99+% Pure Elemental Copper with trace Ag/As) |
| Geology Guide group | Minerals (8 Major Chemical Groups) |
| Mineral Group | Native Elements |
| Mohs hardness | Mohs 2.5–3 |
| Texture / habit | Branching arborescent ('tree-like') dendrites, wires, and distorted dodecahedra |
| Density | 8.94 g/cm³ |
| Lustre and cleavage | Salmon-red metallic lustre on fresh cuts, weathering to green patina; hackly malleable fracture |
| Geological setting | Basaltic lava vesicles (e.g., Keweenaw Peninsula, Michigan) and oxidized copper caps |
| Diagnostic feature (Geology Guide) | Branching, tree-like ('dendritic') metallic masses (density 8.9 g/cm³, Mohs 2.5–3) with a warm copper-penny red sheen on fresh surfaces, a green weathered patina, and a jagged 'hackly' malleable fracture. |
| Formula | Cu |
| Habit | Dendritic masses and sheets |
See Also
- Malachite — the green copper carbonate that forms as it weathers
- Chalcopyrite — the main copper ore
- Copper — the element