Feb 18, 2009 ... Turquoise is possibly the most valuable, non-transparent mineral used in jewelry. It has been mined since at least 6000 BC by Egyptians.
Feb 19, 2013 ... I love all turquoise! The list of my ten favorite American Southwest turquoise mines have produced some of the most beautiful gems in the world ...
Nevada has several public mining sites where you can pay to dig for several varieties of minerals. The most popular and valuable are opals and turquoise.
Dec 13, 2013 ... But the local desert had active turquoise mines. Most of them had been worked prehistorically by American Indians, who treasured the mineral.