NASA Scientists Explore California’s Driest Desert for Clues to Hidden Copper Systems

California’s Mojave Desert has long drawn tourists, hikers, and off-road enthusiasts. Now, it has become the focus of a different kind of expedition, one that could help scientists understand whether valuable copper-bearing mineral systems lie hidden beneath the state’s rugged landscape.

A team of researchers from NASA’s Jet Propulsion Laboratory (JPL) and the U.S. Geological Survey (USGS) recently investigated the high desert near Barstow in San Bernardino County after a NASA sensor detected an unusual mineral “fingerprint” from the air.

Their target wasn’t gold or gemstones. It was topaz hiding in plain sight.

While topaz is popularly known as a precious gemstone, with shades of blue, yellow, orange, and red, scientists were interested in it for a different reason.

The presence of topaz can signal the same volcanic conditions that produce porphyry copper deposits, which are one of the world’s most important sources of copper.

Sometimes doing science involves taking a hike 🥾@nasa @usgs GEMx scientists hiked in California to study minerals near Earth’s surface. The data they collected on the ground will help verify similar measurements from an instrument on an aircraft and the @Space_Station. pic.twitter.com/RJ6r2UK3lb

— NASA Earth (@NASAEarth) June 12, 2026

Porphyry copper deposits are formed when magma and hot water rise through Earth’s crust, chemically changing the surrounding rock over millions of years, according to JPL.

The process often occurs in subduction zones, where one tectonic plate dives below another. One such geologic feature, the North American Cordillera, stretches from the Canadian Rockies through the western U.S. and into Mexico.

In addition to copper, which is the third most-used metal in the world after steel and aluminum, porphyry systems can also contain critical minerals such as molybdenum and tellurium, according to JPL.

According to geoscientists, these critical minerals are used in applications ranging from steelmaking to solar panels.

For the scientists working in the Mojave, however, the goal was not to announce a major mineral discovery.

A team of experts from the USGS and JPL trekked across public land near Barstow to collect pieces of a volcanic outcrop that was detected by NASA’s sensor.

The samples will help researchers determine whether the topaz-rich rocks point to a deeper porphyry system below the surface or simply represent an isolated geological feature.

Mineral Mapping Technique

The investigation was guided by AVIRIS-5, the latest version of NASA’s Airborne Visible/Infrared Imaging Spectrometer, which was built at JPL in Southern California.

The instrument recently took to the skies as part of the NASA-USGS Geologic Earth Mapping Experiment, according to NASA.

AVIRIS detects the unique spectral signatures of minerals by measuring the wavelengths of light they reflect.

The broader goal of the Geologic Earth Mapping Experiment is to identify potential sources of critical minerals across the American West, including in waste rock from active and abandoned mines.

Whether the Mojave site ultimately proves to contain economically significant copper deposits is yet to be seen. That answer will require more fieldwork, testing, and analysis.

For now, the expedition serves as a reminder that even in a state as heavily studied as California, scientists can still uncover new clues hidden in plain sight.