Hi Cheech!
That type of marble is called a sulphide. The figure is made from fire clay so that it won't get destroyed by the hot glass. They were hand-made in Germany and maybe other places in the 1800s originally but yours is a contemporary one hand-made by a well known marble maker named Jim Davis. He passed away in 2007 but many of his marbles live on. Contemporary marbles are my weak area, so I can't tell you much as far as value, but assuming this one is large-ish (1.5-2") and in good shape, I would think at least $50, maybe a lot more if this was an early one or rare one. I saw a couple of them on Block's auction that sold for $55 each.
Good find!