I found his signature on this, but he signed his full name, of course this one is larger and has a flat bottom. https://www.worthpoint.com/worthopedia/c-herman-leonhardt-1948-2011-signed-4656954971
TSo, I'm guessing you're saying that Herbert may have made this marble. Perhaps he liked Jack's marbles and decided to make one of his own. Guess I'll leave it that he did, since his initials are indeed HCL.
I don't believe he made this marble, as all I see are bowls and such created by him. But the marbles that Jack Hahn made are very similar in both design and size. Why would Herbert sign Jack's marble?
Thank you, and I'll check to see if he made anything like this one. It's approximately 2 1/4" wide. May Mr. Herman C. Leonhardt rest in peace. The marble is gorgeous.