1. A big Meteorite impact can`t be seen or reproduced in a labratory. All numbers are not measurable and out of imagination.
2. The extreme rarenes of this events.
3. There are no other comparable natural glasses. Obsidian is quite similar but with a impotant difference. Tektites contain about 100 times less OH^- Groups. No other natural glass is so poor in "water" to be able to be a reference.

»When you throw a stone in the water with a very low angle. A splash will appear which goes in one direction before the stone sink.«
The "same" was happening at the Moldavite Impact. During the so called "Jetting phase" (that`s the moment directly after the first touch of the Meteorite with the Earthsurface) there result an extreme hot ray of steam or even plasma, made of the first layer hit by the meteorite. This ray shot in eastern direction.

Up in the atmosphere the material cooled down and condensed still very hot, to liquide glass. It rained down in the so called strew fields many hundret kilometers east. The size of the Meteorite and the low angle of the impact is essential to create Tektites. That`s why not all big meteorite craters produce Tektites.