First the term "crystal" has a rather vague meaning in reference to glasses. It usually means a glass that has a high lead oxide content, but it does not have a crystalline structure in the scientific sense. Some features of high lead content glass are : it is more easy to cut and polish than many glasses, it has a high refractive index and sparkles more than most glasses, it is quite heavy. Lead glass "crystal" has long been very popular in northern Europe. However the traditional Bohemian glasses used by Moser and others often did not contain lead. Likewise some of the famous glasses in the Venice area, including the islands, contained no lead. You will pay a small fortune at auction for the best old examples from Moser and others that contain no lead. Moser also has used lead glass and some very unusual glasses including those with a high rare earth cotent. These days most like a clear glass with an uncut bowl so that they can see the wine well. In the past many were not interested in the looks of the wine, and many wine glasses were highly decorated works of art. Some of the wines in the past were not very clear, so havng these wines somewhat hidden perhaps even was an advantage.
My mailbox is always full to avoid spam. To contact me, erase snipped-for-privacy@webtv.net from my email address. Then add snipped-for-privacy@yahoo.com . I do not check this box every day, so post if you need a quick response.