LIBYAN DESERT GLASS polished faceted specimen Top grade One side is natural ( not polished ) Weight: 3.3 grams / 0.12 oz Size: 28*13*7 mm / 0.99*0.46*0.32 inch Origin: Egypt The item in our pictures is exactly the stone you will receive Libyan Desert glass, or Great Sand Sea glass is an impactite found in areas in the eastern Sahara. Fragments of desert glass can be found over areas of tens of square kilometers. Studies show the Libyan desert glass formed about 29 million years ago. The glass is nearly pure silica, which requires temperatures above 1,600℃ to form, and that is hotter than any igneous rock on Earth. Few mineral relics survived from whatever caused the melting. Within the glass are rare occurrences of high-temperature minerals, including a form of quartz called cristobalite