Thermoplastics, in basic terms, are melt-processable plastics (materials that are processed with heat). When enough heat is added to bring the temperature of the plastic above its melt point, the plastic liquefies (softens enough to be processed).
In the U.S., diamonds have been found in Arkansas, Colorado, Wyoming, and Montana. In 2004, the discovery of a microscopic diamond in the U.S. led to the January 2008 bulk-sampling of kimberlite pipes in a remote part of Montana.
Kelsey Lake Mine. At present, there are no commercial diamond mines operating in the United States. The only commercial mine with recent activity is the Kelsey Lake Diamond Mine, located near Fort Collins, Colorado on the state boundary between Colorado and Wyoming.lthough millions of carats of diamonds are consumed each year in the United States, very few diamonds are domestically produced. The only active diamond mine in the country is the Crater of Diamonds Mine near Murfreesboro, Pike County, Arkansas.