The Minerals of Earth's Crust/Part I: Eight Elements Dominate Earth's Upper Layer

摘要

Scientists, and more than a few amateurs, have discovered nearly 4,000 different mineral species in the Earth's crust. Yet, by carefully analyzing rocks and minerals, scientists have come to the fascinating conclusion that 99 percent of the Earth's crust is composed of just eight naturally occurring elements: oxygen, silicon, aluminum, iron, calcium, sodium, potassium, and magnesium. These major elements of the Earth's crust have been shown to be the product of atomic fusion in stars like our sun. Our sun, a rather average star, cannot produce any elements heavier than iron (atomic number 26). The formation of heavier elements requires a massive amount of energy, far more than our sun can produce. Such energy can only be generated by an exploding star, what we call a nova or supernova! If eight elements make up 99 percent of the Earth's crust, that leaves a meager 1 percent to account for the remaining 84 elements. Yet, these elements make all the difference in the world when it comes to the great variety of known mineral species. In spite of their limited quantities, we often find these scarce elements concentrated in ore veins and deposits rich enough to be worked productively.