William- Marbles are making a comeback for several reasons. A lot of the collector interest is driven by middle aged people trying to get back the stuff their mother’s threw out while they were in college or lost to the neighborhood hustler (haha,but true). There is a tremendous resurgence in art marble making. From West Virginia to California, the furnaces and torches have been fired up. Many of these studios are offering classes in marble making. Wheaton Village in Millville, NJ has a Marble Weekend following the National Marble Tournament, which is held in Wildwood, NJ. My family went last year and met a lot of the young artists that have led the new wave. The game of marbles is starting to make a comeback because it is so basic and simple. Since marbles are one of the oldest toys, and is the oldest mass produced toy (see the Akron marbles website),it seems only natural that “what was old is new again”. It is a game of skill that can be played under any conditions and modified with mutually agreed rules. It can be played for fun or keeps. There are no flashing lights, inappropriate violence or language (unless you miss) and does not become obsolete when a new gaming platform comes out. It still teaches hand/eye coordination, fine motor skills and sportsmanship without the possiblity of physical retaliation during the match. As far as glass verses stone, stone marbles make better shooters than glass due to better density and hardness. Glass marbles are fine to learn on, and many players use them successfully in tournament play. My daughter has shot in the National Marble Tournament for the last four years, representing Perry Hall, MD. Most upper rung players shoot with agates. Some have used other stone marbles- some are more brittle and chip/crack. You can find agates and other stone marbles on e-bay and other websites. You can find some bargains, if you look. For the game of ringer (the National Tournament game), the largest shooter you can use is 3/4″. The rules can be found on the tournament website (among others). Good luck with you daughter-