Which layer of Earth has the greatest variety of minerals?

• A. Core
• B. Mantle
• C. Crust
• D. Outer Core

Answer: (C)

Mineral variety tracks the diversity of rocks and the conditions under which they form. The crust hosts a wide range of rock types—granite, basalt, sandstone, limestone, shale, and many metamorphic varieties—each with its own mineral assemblage. Weathering and alteration continually produce additional minerals, and metamorphism can create new minerals as rocks recrystallize under different temperatures and pressures. In contrast, the mantle is dominated by a relatively small set of high-temperature silicate minerals like olivine and pyroxene, so its mineral diversity is much lower. The outer and inner cores are mainly metallic iron-nickel with only a few sulfide or oxide phases, not a broad mineral variety. So the crust has the greatest variety of minerals.