Copper natural pyramid 168g, USA

Copper is relatively rare in the Earth's crust. Its content is estimated to be 55-70 ppm (mg/kg). In seawater, its concentration is only 0.003 milligrams in one liter. It is believed that there are approximately 1 billion hydrogen atoms for each copper atom in the universe. Pure copper is found in nature, but rarely in large quantities and is therefore mainly found in compounds. Elemental is more abundant near Lake Superior in North America. It is most often found in the form of sulfides.