Cyrus Wadia makes pure pyrite nanocrystals in his lab at the University of California, Berkeley. Credit: Jen Siska

Fool's gold, also called pyrite or iron sulfide, can be unearthed just about anywhere, from the hills of California to the villages of Yunnan Province in China. But instead of digging pyrite up, researcher Cyrus Wadia is making pure nano­particles of the compound from iron and sulfur salts in his lab at the University of California, Berkeley. His ultimate goal is to turn fool's gold into real treasure: an inexpensive solar cell.

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