Hi Dale;

Sounds convincing when you laid them side-by-side. When I used to fly to work on a daily basis in a private plane over Central Illinois, I used to fly over the Owens-Corning glass works in Ottawa . . . There was an ancient fault there that brought up fused silicon dioxide, and the entire countryside (mining area) looked like a large, green Coke bottle. I used to circle occasionally and just take in the grandure of acres of crumply green glass. I suspect that much of the "cheap" glass we observe has enough impurities (or whatever) that refraction, when viewed as a thicker wall as in a bottle or windowpane, or as fibers, when embedded in a medium such as epoxy, brings this charactertic out. In retrospect, there has to be a happy medium between "bottle glass" and "fine crystal" that will yield a clear cloth. Perhaps someone allied with the glass industry can offer a clearer picture.

Good and practical observation Dale (as usual), Best Regards, Spidey

PS - I'll be on a business trip all next week, so if anyone shows up on this thread, suck-em-dry for info! 8-)