Most of the world's platinum comes from?

A) the base of ancient stream gravels
B) veins formed by metamorphism
C) veins formed in calderas
D) large mafic to ultramafic intrusions
E) none of these

Platinum

A dense, malleable, ductile, and highly unreactive precious metal used in jewelry, automotive catalytic converters, and various industrial applications.

Mafic to Ultramafic Intrusions

The intrusion of magma rocks ranging from mafic (rich in magnesium and iron) to ultramafic (extremely rich in magnesium and iron) compositions, important in the formation of various ore deposits.

Veins

Mineral deposits that fill cracks in rocks, often distinguished by their different materials from the surrounding rock.