(I apologize for the wall of text)
TL;DR Earth glide is not clarified enough and has up to three issues regarding how the ability is temporarily gained.
1) What happens when the glider ends the duration of the ability in stone?. (All) What happens to passengers? (Oracle only)
2)Must passengers be willing?(Oracle Only)
3) Do passengers gain the ability like the oracle, which is shown in the split duration, or are they merely pulled by the oracle, and the extra strain causes the reduced duration?(Oracle Only)
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So I know that there are multiple posts for clarifying the earth glide rules but I think I have narrowed it down to the main issues. First, the text for the three ways that I know of to gain a temporary earth glide movement.
Earth Glide (4th Level Spell)
"The target can pass through stone, dirt, or almost any other sort of earth except metal as easily as a fish swims through water, traveling at a speed of 5 feet. If protected against fire damage, it can move through lava. This movement leaves behind no tunnel or hole, nor does it create any ripple or other sign of its presence. It requires as much concentration as walking, so the subject can attack or cast spells normally, but cannot charge or run. Casting move earth on an area containing the target flings the target back 30 feet, stunning it for 1 round (DC 15 Fort negates). This spell does not give the target the ability to breathe underground, so when passing through solid material, the creature must hold its breath."
Earth Glide (Ex) (Deep Earth Bloodline 15th Level Power)
"At 15th level, you can glide through any sort of natural earth or stone as easily as a fish swims through water, with a burrow speed equal to half your normal speed. You do not leave a tunnel or trace of your passage. You can use this ability for 1 minute per sorcerer level each day. The duration need not be continuous, but it must be used in 1-minute increments."
Earth Glide (Su) (Minimum 7th Lvl Stone Oracle Revelation)
"You can pass through stone, dirt, or almost any other sort of earth except worked stone and metal as easily as a fish swims through water. If protected against fire damage, you can even glide through lava. You glide at your base land speed. While gliding, you breathe stone as if it were air (you do not need to hold your breath). Your burrowing leaves behind no tunnel or hole, nor does it create any ripple or sign of your presence. A move earth spell cast on an area where you are flings you back 30 feet, stunning you for 1 round unless you succeed on a DC 15 Fortitude save. Activating this ability is a free action. You can glide for 1 minute per day per oracle level. This duration does not need to be consecutive, but it must be spent in 1-minute increments. You must be at least 7th level to select this revelation. You can bring other creatures with you when you glide, but each passenger costs an additional minute per minute of travel."
So first off, one thing that strikes me as off is that the Oracle version is hands down the best. One would think that it would be comparable in strength to the Earth Glide (Spell), since they are each gainable at approximately the same level, but the spell is worth. It is only 5 feet, whereas the oracle's is full speed, does not allow breathing, and also only allows a single target, and is 1/6th the duration. Additionally, in terms of action economy it is worse as it requires a standard action to cast, whereas the other 2 are free actions. So in this comparison the Earth Glide (Su) is better.
Now, comparing the Oracle ability and the Sorcerer. First off, the Sorcerer ability is an Extroardinary and is usable in anti magic zones, so it gets a one-up in that circumstantial field. However, it also does not state the user can breathe and is also self only, making it by and large worse than the Oracle ability.
Now, that argument was kind of tangential, really it was just a thought process in my head to compare the abilities, but I think it may help other people. Now, on to the three main issues with this poorly clarified and written ability:
1) What happens when the glider ends the duration of the ability in stone?. (All) What happens to passengers? (Oracle only)
Now that's the main issue for the spell and the sorcerer ability, but the oracle ability has two more issues along with it.
2)Must passengers be willing?
and 3) Do passengers gain the ability like the oracle, which is shown in the split duration, or are they merely pulled by the oracle, and the extra strain causes the reduced duration.
Now, all three of these issues are problematic because there are no rulings to specifically state the solutions. For the 1st problem, tangential solutions exist in other mechanics, such as: being shunted by a failed dimension door, ending movement in an illegal space, and having to dig 5-ft/rnd when trapped in the Earth plane. However none of these directly answer the issue.
With the 2nd problem, the ability does not clearly state the willingness of passengers. In other spells willingness is specifically stated, and the argument for it being usable on unwilling creatures is supporting by the final paragraph in the Oracle's Revelation ability section, which reads:
"Unless otherwise noted, the DC to save against these revelations is equal to 10 + 1/2 the oracle’s level + the oracle’s Charisma modifier."
However I don't personally think it allows the ability to be used on unwilling targets.
The 3rd issue is really down to interpretation I think, and I would rule that they do not gain the ability, and that when contact is broken they will then be acted upon in accordance with the resolution for Issue 1.
I'm interested in hearing other opinions.