I have some questions about the products of "dry" (as in non-molten) eruptions.
Mainly about pumice and that red and/or black lava rock that looks like it wanted to be pumice when it started out, but is a lot denser.
Now I know not all pumices are the same. In fifth grade school most of us had that cool teacher who shows you the rocks that float on water and all that and that pumice was completey innocuous to handle.
Yet when I was a greenhouseman we used pumice stones that imitated the heavier lava rocks to make walls and banks for trade show displays and you absolutely had to wear leather gloves to handle these pumice stones. These pumice stones had quarter inch on a side shiney flat inclusions the first pumice stones lacked. But still very friable. Like having razor blades pieces hidden in dry bread.
One time I warned one of our decorators sharply against picking one of these pumice stones up bare handed. He looked at me like I grew a second head, picked up the pumice piece bare handed and pushed it hard into place in the mozaic of the bank we were building.
Thirtyfive stitches of damage in seven cuts to his right hand alone. AND he was flying to Hawaii for a two week vacation that afternoon. I really felt bad about not physically stopping him but thought that would have been a bit much. Before hand.
So my questions regarding pumice, (and cinder is it?) are
Are pumices closer to open cell foam or closed cell foam?
What are the production differences between safe to handle pumice vs oh dear Lord, no don't handle that pumice? Both were classic grey, but the dangerous stuff had dense non-fluffy black streaks in it. Both still floated.
What do you really call the red and black lava rocks used in construction and where do they fit in the order of pumice-like effluvia?
I saw deep valley in what looked like a dry plain once. The walls of the valley showed that what I thought was "hole" was actually the original pre-eruption ground level and that for as far as the eye could see everything was buried under several hundred feet of breadbox sized rocks of that denser than pumice pumice-like rock. Explained why it was a dry plain if nothing else.
My question in this case is:
How deep does volcanic cinder have to be before it starts crushing down like snow into glacial ice?
I would have to think pretty deep given the light weight and structural strength of cinder compared to snow.
If it does crush down without going into a liquid phase, where does the trapped pockets of gas go? One big pocket somewhere? I wonder that about the glacial ice as well.
That's all I have at the moment. I know I have more.