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).
Where diamonds are found in the United States - Wyoming. Diamond Kimberlite pipes have been found in Wyoming, near the Colorado-Wyoming state line area referred to as the Aultman, Ferris and Schaffer kimberlites. The Herkimer Diamond Mine and the Ace Of Diamonds Mine - New York.
The only active diamond mine in the country is the Crater of Diamonds Mine near Murfreesboro, Pike County, Arkansas. There, recreational prospectors have been finding up to a few hundred carats of diamonds per year since the early 1970s. Most of the stones are white, yellow, or brown in color, but a wide range of diamond colors has been found at the mine. See photo at the top of this page.