Happy Minerals Day! To celebrate, we are highlighting smithsonite. Smithsonite is a zinc carbonate mineral associated with sphalerite-bearing deposits in north Arkansas and sphalerite-bearing quartz veins in the Ouachita Mountains. The photo above illustrates its yellow color from cadmium and its botryoidal shape or habit. It can also form rhombohedral crystals (see additional photo). Smithsonite and other zinc minerals were important ores in the zinc and lead district of north Arkansas in the late 1800s and early 1900s. Zinc is used to galvanize iron and steel to prevent corrosion and to make brass and alloys for die-casting. Although, we are a net exporter of zinc ores and concentrates, the United States is largely dependent on foreign sources for refined zinc used in manufacturing due to limited smelting capacity. For this reason, zinc was added to the list of critical minerals by the U.S. Geological Survey.
Smithsonite is named in honor of James Smithson, the founder of the Smithsonian Institution.
For more information about critical minerals or other minerals in Arkansas use the link below:
https://www.geology.arkansas.gov/minerals/critical-minerals.html
Office of the State Geologist Blog 