It's name means "Turkish stone" from the trade route to Europe From Turkey. Turquoise was thought to be amorphous till 1911 when they were found in Virginia (U.S.) On fresh fractures it has a waxy or vitreous luster. From 482F/250F the popular sky blue color turns into a dull green. It is also susceptible to light perspiration, oils, and cosmetics, as well as loss of natural water content. Turquoise Rings should be removed before hand washing. Polishing makes color more intense. The pores are closed by immersion in oil or paraffin or by using a plastic solution and so the stone hardens.