Role of the U.S. Geological Survey (USGS)
The USGS reports deposits that seem likely to contain gemstones. It is not a function of the USGS to exploit such resources.
USGS geologists perform continuing research on kimberlites, the initial source of diamonds. Not all kimberlites are diamond-bearing, and some of the research is directed to learning what indications you look for during exploration to distinguish fertile from barren kimberlite. USGS geologists are compiling a U.S. map showing the locations of known kimberlites.