Marble (toy) conventions. Additionally, many glass artisans produce art marbles for the collectors' market only, with some selling for thousands of dollars. Marbles are made using many techniques. They can be categorized into two general types: hand-made and machine-made. Marbles were originally made by hand. Stone or ivory marbles can be fashioned by grinding. Clay, pottery, ceramic, or porcelain marbles can be made by rolling the material into a ball, and then letting dry, or firing, and then can be left natural, painted, or glazed. Clay marbles, also known as "crock marbles" or "commies" ("common"), are made of slightly porous clay, traditionally
Toy train trains made of tinplate weren't scale at all, made to unrealistic, whimsical proportions similar in length to modern HO scale, but anywhere from one and a half to two times as wide and tall. Some adult fans of toy trains operate their trains, while others only collect. Some toy train layouts are accessorized with scale models in an attempt to be as realistic as possible, while others are accessorized with toy buildings, cars, and figures. Some hobbyists will only buy accessories that were manufactured by the same company who made their trains. This practice is most common among fans of