A few people, such as myself are still making stone marbles by hand. Maybe I'm the only one? I don't much care for alabaster as it is so soft. Jasper and also glass are more interesting. Jasper can have some great patterns, and glass can't be beat for vibrant color.
I perfer to make marbles and spheres with grinding wheels not by a marble making machine. This means that the marbles and spheres are never the same size, and sometimes they have subtle variations in their shapes. I'm planning to exhibit my marbles and spheres at the Santa Clara Gem and Mineral Show April 17-19 in California. After that, I expect to finish my website offering stone marbles, spheres, and even eggs made of every kind of stone or slag glass I can get. I've even taken on commission work.
If anyone else is making marbles this way, please chime in.