Answered By: Beth Hylen Last Updated: Nov 21, 2016 Views: 147
Since its discovery in the 1930s, there has been a great deal of debate about how Libyan Desert Glass was formed.
The Corning Museum of Glass website (www.cmog.org) shows the general consensus:
"In nature, glasses are formed when sand and/or rocks, often high in silica, are heated to high temperatures and then cooled rapidly. The intense heat and force of meteoritic impacts on the earth and atmospheric explosions, millions of years ago, created the natural glasses that we know as tektites and Libyan Desert Glass. Libyan Desert Glass [such as CMoG 2000.7.1] is found in the Sahara’s Great Sand Sea, which spreads across the border of Libya and Egypt. The large silica glass field there is believed to have resulted either from a meteoritic impact or from a comet exploding in the earth’s atmosphere.
Tektites [such as CMoG 2000.7.4] were created by meteoritic impacts. These impacts melted the meteor and the surrounding terrestrial rock, creating the spherical forms, comma shapes, drips, and splashes characteristic of tektites. Tektites are formed at a much higher temperature than volcanic glass (obsidian) and under tremendous pressure.
Natural glass may also be formed by explosions on earth. Volcanic glass, known as obsidian [CMoG 63.7.12], is created when lava cools rapidly, becoming rock in a glassy state, just as boiled hard sugar candies are sugar in a glassy state."
To read more about different types of natural glasses: http://www.cmog.org/article/glass-nature
I am also sending a brief bibliography with more detailed information about Libyan Desert Glass. (This is a new list -- I copied my answer to you into the bibliography)
I added the pages on natural glasses from:
Brill, Robert H. Chemical analyses of early glasses. Corning, N.Y.: The Corning Museum of Glass, 1999. 2 v. (335; 553 p.)
Do you have access to the JSTOR database? It has extensive full-text articles relating to the topic. The database is available in many college, university, and large public libraries.
If you need more in-depth information about Libyan Desert Glass, I will be happy to refer you to our Science Curator.