where is an active diamond mine in the u.s.
IT'S ARKANSAS The United States' only active diamond mine is located near Murfreesboro. It is operated as a tourist attraction. Diamonds are also Arkansas' state gem.  (MY SOURCE IS BELOW) Northern Colorado was home to the country's only working diamond mine, Kelsey Lake, until its closure several years ago because of legal troubles.. (SOURCE BELOW). Source(s): http://www.gypsysue.com/statesarkansas.h...