I'm hoping some one can point out some rules I've missed, or some rules extrapolation I've overlooked that might explain some of these questions.
There are different descriptions for Earth Glide depending on what the source is. A quick search gives me 5 different versions of Earth Glide, with differences varying from subtle to major between them.
- Earth Glide spell from the Advanced Races Guide for Svirfneblin
- Deep Earth Sorcerer Bloodline in the APG
- Rules for monsters with Earthglide; i.e. Earth Elementals
- Earth Wizard School from the APG
- The sort of nebulous description "you gain Earth Glide" from the Elemental Body spells
Can you run while Earth Gliding? The spell doesn't allow it, but it also only allows you to move 5 feet. Are, as the descriptions indicate, only some forms of Earth Gliding susceptible to the Move Earth spell stun? Are Earth Wizards the only ones at risk of shunting? What happens to a Sorcerer or a Wizard using the ARG spell when their duration ends?
Is it a movement type? Is it an extension of burrowing? It doesn't list a speed. Some descriptions start with "While burrowing..." but others don't. Does it, in those cases, use a creature's burrow speed? Does it ever confer a burrow speed? Which Earth Gliders can use it as a five foot step, and which can't?
Can you be partially Earth Gliding? Does this confer cover? Does it affect actions being performed? Can I attack a creature directly above me while completely submerged? Can I swing a weapon out of a hillside? Does it affect my swing, like trying to attack underwater? Would Freedom of Movement negate that penalty?
Some descriptions care about whether or not the earth is worked. What does worked really mean? Is a man-made pile of rocks worked? What if there are sizable gaps between rocks? Or even just rather tiny gaps? If I take those same rocks and orient them so they form a wall, with little to no gaps, is that worked? What if some one uses mortar? What if I smooth the stones so they fit very snugly? Say, like the walls of Machu Pichu? What if they are formed into into perfect cubes? Is compacted earth worked? How about baked clay, if we assume there is no straw or additives?
Do Earth Gliding creatures without Tremorsense have to worry about gliding down through the roof of a large cavern? Or unexpectedly emerging any other time? In general, how does a creature know what's going on around them while Earth Gliding?
Do I have to be moving to Earth Glide? What if I just want to put my head through to see the other side? Can I stick my hand in to hide a held object from sight? Can I submerge my feet to anchor myself from a Reverse Gravity spell? What if I'm not moving by choice? Can I Earth Glide to avoid being pushed into a wall? Can I glide into a wall while falling gain control of my movement? Can I glide part of my body to slow my descent? What if I glide instead of hitting the bottom?