The tube is hollow and is completely encased in a Quartz crystal matrix. Talk about a conversation starter. According to the time it takes for quartz to crystallize and the known time as the existence of humans on this planet, there's no logical explanations for this specimen if found near Mt. Adams in the Washington Cascade Mountains. I'm sorry to have to part with it but times are the way they are.I know you'll be as dumbfounded as I was when I held in my hand for the first time. 86 grams and measures appx.