Moldavite and Desert Glass both have one thing in common. Both are thought to have been created by a meteor impact.  Moldivite is perhaps the best known and most sought after impact site "gemstone - and this term is used loosly as it is acutally glass and not a stone" and  was named by A. dufrnoy from Moldauthein in Bohemai where it occurs.  It is sometimes cut and polished as an ornamental stone under the name of a pseudo-chrysolite. It is often called Bout-illenstein because of its its bottle-green glass color,  and it usually appears as an olive green to dull greenish viterous substance.  Moldavite glass is belived to have formed 15 million years ago during the impact of a giant meteorite in present-day Nördlinger Ries. Splatters of rocks that were melted by the impact cooled while they were actually airborne and most fell in central Bohemia - traversed by river Vltava (Moldau in German). As such the glass can be found in the Czech Republic, Austria, Germany and Moldova.  It is one kind of tektite. 

The total amount of Moldavite scattered around the world is estimated at 275 tons. There are now only four moldavite mines that are in full operation in the Czech Republic. It is predicted that in less than ten years from now commercial Moldavite mining will come to an end. After this time, there will be virtually no appreciable amount of gem-grade Moldavite left in the ground.There are typically two grades of moldavite: high quality, often referred to as museum grade,(above left) and regular grade (right). Museum and regular grade moldavite can be told apart by the way they look--the regular grade pieces are usually darker and more saturated in their green colour, and the surface is seen as closely spaced pitting or weathering. This type sometimes appears to have been broken apart from a larger chunk. The museum grade has a distinct fern-like pattern and is much more translucent than the regular grade. There is usually a fairly big difference in the price between the two. The museum grade "flower bursts" are much more prized by the connoisseur.

High-quality moldavite stones are often used in hand-crafted jewelry and thus enter the market away from mainstream jewelry fashions, more centered around art and craft, and as such have gained an almost cult status.  Moldavite of good quality can fetch a very high price, but even general comparisons put the stone's value at as 'that of higher quality large Amethysts.  The above photos demonstrate the three common ways in which modavite will be mounted.  The far left is wire wrapped and the stone is left pretty much in natural form.  The most expensive use will be the center cut in which a good stone is faceted; however, do not be deceived by unscrupulous sellers.  Most cut or faceted moldavite will be very small in size - as in about the size of your small fingernail.  A lot of waste occures to get a good facet and many stones aren't pure enough for this.  Larger examples exists but they will run into thousands of dollars. 

The far right stone is several carets in size and is the most common "moldavite" on eBay.  It is also a FAKE.  It is highly doubtful a very large moldavite stone will every appear on open auction on eBay or anywhere else on line.  They are far too valuable and they will not be started a low opening bid price or sold for a few dollars.  What is often put out on eBay are colored CZ or lab grown Quartz stone and even cleverly cut glass.  Don't be taken in by these auctions.

 The latest stone craze to hit eBay and the collector community is Desert Glass, also called Sahara Desert Glass, Libyian Glass, or Desert Gemstone or one of the other variants.  Like Modavite it is a metor impact glass pale yellow to green in color formed about 28.5 Milliom years ago. In the glowing heat sand melted, splashed up in the air and spread over a 4000 square kilometers sized area in West Egypt. Like with sand, the essential constituent is silicium dioxide, a possible hint of iridium is a indicator for the extraterrestrial origin. Already in palaeolithicum, about 10000 years ago, men discovered this glass. It was used as a substitute for flintstone, one can find artefacts formed as sharp blades and graters. The old Egyptians found a less pragmatic application for this special stone. Even in those times it was considered to be precious and so it become part of religious objects like Tutenkhamon's amulet, there as a carved scarab. Nowdays the Libyan Desert Glass is not only attractive for collectors, esoterism attributes energies for a long and prosperous life to the seldom "rock of the god". Today the way to the find area near the Egyptian-Libyan border leads hundreds of kilometers through arid, desert scaped regions and its collection is highly restricted.

The source of the glass has been hotly debated, but a fairly recent article in  Science Magazine, planetary scientist Farouk El-Baz  discovered "the largest crater yet found in the Sahara," and is suggesting that it has the right characteristics to answer a long-standing mystery.  Since 1932, pieces of Libyan Desert Glass weighing as much as 16 pounds have been picked up by scientists  in a 60-by-100-kilometer (35-by-60-mile) area of the desert of southern Egypt near the Libyan border. Study of the glass has revealed the unmistakable isotopic signature of an asteroid impact, but the source crater has never been found -- until now.

El-Baz says that the crater he discovered is 30 kilometers in diameter, large enough to be the source of the glass.  The crater is located in the Gilf Kebir plateau, an area previously identified by researcher Philippe Paillou of the Observatoire Aquitain des Sciences de L'Univers to be the largest impact crater field on Earth.  The extreme conditions of the Sahara desert act to preserve impact crater structures, though the crater that El-Baz discovered and named "Kebira" (an Arabic word meaning "great" or "powerful") was difficult to see because of its large size and dissection by ancient rivers during a time when the region was wetter than it is now.

Libyan Desert Glass is generally yellow in color. It can be very clear or it can be a milky, even bubbly light yellow. Some fragments have dark bands and swirls of brownish material. It is in these dark areas that some of the melted comic body is believed by some to be preserved. Libyan Desert Glass was used in ancient times as a gem stone for the Pharaohs and remains a highly prized impact glass for collectors today.