Is This A Geode Or Tektite

[Carl1234]

Not sure what this is. It seems either crystal or glass and lighter than it seems it should be. Thought of a geode due to it sounding hollow ish  smooth shiny surface  

 

any thoughts 

 

 

[jasong]

A cobble of some sort of volcanic material by the looks of it. You'd have to do some testing. Glassy material should give a conchoidal fracture. The hollow sound could be from air bubbles inside it, as there are air bubbles on the outside visible.