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 Marbles were originally made by hand.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 toy safety, every country has its own regulations. But since the globalization and opening of markets, most of them try to harmonize their regulations. The most common action for younger children is to put toys in their mouths. This is why it is of utmost importance to regulate chemicals which are contained in the paintings and other materials children's products are made of. Countries or trade zones such as the European Union regularly publish lists to regulate the quantities or ban chemicals from toys and juvenile products. There have also been issues of toy safety regarding lead paint. Some toy