The process I use for making marbles is considering Lampwork. Many people confuse it with glass blowing, Lately I have been taking glass blowing classes as well - hopefully I will make a large face marble when my skills improve. Here is a large plate and cup I made recently.
![](https://i.etsystatic.com/isbi/c4f486/4509465292/isbi_fullxfull.4509465292_lplg920q.jpg?version=0)