A new Rice University study this week in the journal Science finds that nature conspires at scales both large and small -- from the realms of tectonic plates down to molecular bonds -- to keep most of Earth's copper buried dozens of miles below ground.

"Everything throughout history shows us that Earth does not want to give up its copper to the continental crust," said Rice geochemist Cin-Ty Lee, the lead author of the study. "Both the building blocks for continents and the continental crust itself, dating back as much as 3 billion years, are highly depleted in copper."

Finding copper is more than an academic exercise. With global demand for electronics growing rapidly, some studies have estimated the world's demand for copper could exceed supply in as little as six years. The new study could help, because it suggests where undiscovered caches of copper might lie.