Looks solid black, but purple in light

[Marian]

Any thoughts on this one?

Looks like a plain black glass marble, but some seams? And swirls inside.

[Steph]

Could have seams.  The last picture might be showing "cold rolls" though.  Where the glass was just a little bit too cool for the rollers to smooth it out.  

It might have been made as a "clearie".  Lots of companies made clearies which are transparent  to be one color but sometimes you can see different colors if you look really close.  

With swirls inside it might be a Champion Agate.