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.
Up-and-coming new diamond deposits are being developed in Canada. Colored stones are mined in a large number of places, with the largest producers being Brazil, parts of Asia (including Sri Lanka, Thailand and Burma), and several countries in East Africa (including Kenya and Tanzania).The world's most important opal deposits are found in Australia.The world's most important emerald deposits are found in Colombia. In my encyclopedia pages on each individual gemstone, there is a list of countries which have produced significant quantities of that gemstone.p-and-coming new diamond deposits are being developed in Canada. Colored stones are mined in a large number of places, with the largest producers being Brazil, parts of Asia (including Sri Lanka, Thailand and Burma), and several countries in East Africa (including Kenya and Tanzania).