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.
Susie Clark, of Evening Shade, Arkansas, found the diamond on Thursday at Crater of Diamonds State Park. The 3.69-carat gem is teardrop-shaped about the size of a pinto bean. Park interpreter said it's the largest of the 122 diamonds found this year.