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.