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.
Outside the earth, diamonds are also common. A recent discovery shows that some stars collapse on themselves, creating giant diamond crystals. In the constellation Centaurus, there lies a white dwarf, that has crystallized into a diamond 2,500 miles in diameter and weighing 10 billion, trillion, trillion carats. While we are still learning about the interior of the earth, current information shows that diamonds are likely the most common gem in nature.