MINNEAPOLIS / ST. PAUL (08/14/2026) — For the first time, researchers at the University of Minnesota Twin Cities have demonstrated that the low-purity iron ore prevalent in Minnesota can be used to create semiconductor-quality iron sulfide, also known as "fool's gold" or pyrite. This discovery could have cost-effective and sustainable applications in future electronic devices and more.
Minnesota is one of the largest iron-producing states, accounting for 75 percent of the nation's ore, which generates over $4 billion in annual revenue. Natural resources such as the Mesabi Iron Range have fueled Minnesota iron production for decades, enabled by the taconite process developed by Edward Wilson Davis at the University of Minnesota.
Pyrite iron sulfide is a unique semiconductor as it absorbs light extraordinarily well, is composed of very abundant elements, along with being non-toxic and cost-effective. Synthesizing high-quality semiconducting pyrite directly from an abundant iron resource like the Iron Range is therefore very appealing, but semiconductors are extremely sensitive to impurities and defects, making this very challenging.
In this work the researchers took iron ore samples directly from the Minnesota Iron Range and demonstrated that they can be used to synthesize semiconductor-quality fool's gold using simple processes. This discovery took the researchers by surprise.
"We realized that pyrite's really not like a typical semiconductor - it is surprisingly immune to impurities," said Chris Leighton, Distinguished McKnight University Professor in the Department of Chemical Engineering and Materials Science and senior author on the paper. "So, we wondered, do we even need the high purity material that we (and everyone else) had been using to make semiconducting pyrite."
The researchers were able to test three different types of iron ore in this process. It turns out that the one that works best — Direct Reduced Grade Taconite — is one of the most commonly used grades available in Minnesota.
"There are all sorts of reasons why you would think this would not be possible," Leighton added. "But, during processing the dirty — or low-purity — iron ores, directly from the Minnesota Iron Range, were easily converted to semiconductor-quality pyrite with no extra purification steps. This happens for reasons that we now understand pretty well."
This discovery could open up a new revenue stream for a global industry, with a broad spectrum of applications in clean energy technologies, based on a natural resource found abundantly in Minnesota.
Future applications of this research could arise in batteries, solar panels, electronics and processes to purify water. The team hopes to continue this research by testing additional types of iron ores, as they come in a vast variety of grades. They would also focus on making not bulk crystals of pyrite with these Iron Range resources, but also thin film samples more closely relevant to devices.
In addition to Leighton, the research team included Yeon Lee and Caitlyn Komar from the Department of Chemical Engineering and Materials Science, Jennifer T. Mitchell from the University of Minnesota Characterization Facility and the Department of Earth and Environmental Sciences, along with Matt Mlinar, Jestos Taguta and George Hudak from the University of Minnesota Natural Resources Research Institute.
This work was funded by the Minnesota Environment and Natural Resources Trust Fund (ENTRF) as recommended by the Legislative Citizen Commission on Minnesota Resources (LCCMR). The ENRTF is a permanent fund in Minnesota that provides funding for the protection and conservation of Minnesota's natural resources. This work was completed in collaboration with the University of Minnesota Characterization Facility and the Minnesota Nano Center.
Read the paper entitled, "Semiconductor-Quality Pyrite FeS2 from Iron Ore," on the APS Journals website.
